Thecus N5550 NAS Server Review

Manufacturer: Thecus Technology Corporation
Product Name: Thecus N5550
Model Number: N5550
UPC: 884956003526
Price As Tested: $599.99 (Newegg)

Full disclosure: The product used in this review was supplied by Thecus

If Forrest is right, and life is like a box of chocolates - i.e. you never know what you're going to get until you bite into it, then NAS devices are definitely like that box of chocolates. You just never know....... Fortunately, this Thecus N5550 turned out to be Benchmark Reviews' favorite flavor - FAST.

The Thecus N5550 is aimed right at the typical small business owner or advanced home user, by virtue of its size and its form factor. With five bays you can have both capacity and redundancy with RAID 5 on a three, four, or five disk array. Want RAID 6 or RAID 10? There are good reasons to do so, and the N5550 supports RAID 0, 1, 5, 6, 10, and JBOD with no trouble at all; plus RAID migration is available, too. The diskless model made it easy to utilize the same drives I have used during previous benchmark testing. I also wanted to test the ability to expand the storage size and migrate from a single disk to RAID 1 and then to RAID 5. In short, I wanted to get my hands dirty....

The Thecus N5550 uses one of the newest Intel Atom Dual-Core CPUs, ticking over at 1.86 GHz, and 2 GB of DDR3-1066 system memory to drive the internals. Two Gigabit Ethernet network ports are standard, with no expansion capability for additional Network Interface Cards (NIC). Five SATA 3Gb/s drive bays offer single disk, JBOD, and RAID 0/1/5/6/10 configurations. The capability for hot spares is available with any of the disk configurations. Thecus employs a single 1 GB flash memory module to store firmware and applications on the N5550 motherboard. This Disk-On-Memory (DOM) acts like the system drive, yet it takes up very little space and uses almost no power.

Benchmark Reviews has tested quite a few NAS products, ranging from the QNAP TS-119 NAS single-disk offering made for home users, to the Goliath QNAP TS-879U-RP 8-Bay NAS for the storage needs of large businesses. We've recently tested the NETGEAR ReadyNAS NV+ v2 NAS servers, which falls in the middle between those two extremes. Let's see how this 5-bay device compares to its competitors.

Closer Look: Thecus N5550 NAS Server

The bottom line with any high performance storage solution is that the number of drive spindles in play is often more important than almost any other factor, assuming that everything else is based on reasonably modern technology. When you combine the higher level of performance with the greater flexibility for online RAID capacity expansion & online RAID level migration, the additional cost of the extra drive bays always looks like a bargain instead of conspicuous consumption. This is the reason more and more people are opting for NAS systems with at least four bays, even though they may not need all that capacity now. What initially looks like overkill in a NAS system might just be the very thing that saves the day some years down the road.

The Thecus N5550 is a relatively small unit, which is arranged in a tower format and should fit in anywhere, in a variety of home or business settings. The standard model is a diskless unit; Thecus doesn't sell them with drives installed, but there are a number of distributors that will bundle the NAS with some sensible drive combinations. The size and weight are a little smaller than the competition: 230mm (H) x 190mm (W) x 240mm (D), and 7.1 kg without drives installed. Each HDD you install will add about 1-1/2 pounds, depending on your choice of drive. Many users will be looking at 2TB and 3TB drives for a unit like this, and they're heavier than most. There are no handles on the unit, which can make it a bit difficult to pick the whole thing up once it's fully loaded. The top and side panels are metal, with a textured powder-coat finish, so they do provide some purchase for occasional transport.

We've all got data that we can't live without, the question is, how long do you want to be without it? Very few people are going to want to live without their important information for any length of time, and a RAID configuration that includes some redundancy is undoubtedly called for. With multiple SATA drives installed, you can have: RAID 0 (Disk Striping), RAID 1 (Disk Mirroring), RAID 5 (Block-level striping with distributed parity), RAID 6 (Block-level striping with redundant distributed parity), RAID 10 (Striped array whose segments are RAID 1 arrays), and JBOD (Linear Disk Volume). The most popular choice is going to be RAID 5 because it offers the highest capacity with built-in redundancy. RAID 6 offers additional redundancy, allowing for continued operation even with two simultaneous drive failures, and this option is available for the Thecus N5550. RAID 6 is very popular for larger NAS units and mission-critical data stores, because if one individual drive fails in a RAID 5 implementation, the array instantly starts operating as a RAID 0 configuration, which has NO redundancy. It stays in that vulnerable state until the array is rebuilt, which is a slow process that generally taxes the system and the remaining drives to the max, and can take several hours to complete.

Opening the plastic front door of the enclosure lets you access each of the five drive trays, with their locking handles. There are barrel locks on each of the handles, and two keys supplied in the accessory kit for them. My advice is to use the locks and think twice before unlocking the release lever. Trust me when I say that you do not want to start accidentally pulling drives out. The drive bays are not marked on the front bezel, the individual drive trays are not marked, and there was nothing in any documentation I could find that would identify Bay 1 v. Bay 5. Consequently, the first time I booted up the NAS and dug through the disk statistics in the web-based software, I found that I had a single drive installed in Bay 5. I'll tell you now (and for some number of months or years, this will be the only place you can find this information...), Drive Bay #1 is on top and Bay #5 is on the bottom. The LCD panel is providing useful information about the RAID system in the image below, and you can also see the backlit Power button, with its blue LED lighting up the universal on/off logo. The smaller button below it is the Reset switch. The four oval buttons below the display navigate through a number of system configuration settings. This is a relatively common feature on mid or high-end NAS products, but the Thecus N50550 goes way beyond this, with keyboard, video and mouse interfaces on the back panel that are fully functional for the normal user.

With the unit safely turned off, it's OK to remove one or more drives and they all slide out the front like this. Each steel-framed tray holds one individual drive in the N5550, and the tray is a common part across several models in the Thecus product line. The trays are not labeled with the chassis slot number. They are all physically identical and you can mix and match them all you want, until you build a drive array and then you had better remember which one goes where. I recommend making your own labels or marking the trays with a Sharpie as soon as you start installing drives into the unit; if you mix them up the NAS won't recognize the array, and worst case you could end up destroying data as you try to figure out which drive is which. Inserting and removing the drive trays was smooth and positive, both with HDDs mounted in the trays and without. The latches acted like a locking lever; once the trays reached the end of their travel, swinging the latch levers the tray firmly into place. It's a sturdy, well designed system for getting the drives in and out. Not that you want to take them out very often, maybe just for spring cleaning once a year!

Around the back of the Thecus N5550, you can see all of the hardwired I/O points. Starting at the top right is a trio of Audio jacks: Line In/Out and MIC In. Directly below them are a single eSATA connector and two USB 2.0 jacks, with an additional pair of USB 2.0 jacks below that. There are no USB 3.0 jacks on the back of the unit - they're all USB 2.0 spec, despite the different color coding for the two pairs. Still on the right side, about half way down are video connectors for VGA and HDMI, which can be used for system configuration in standalone mode, and as a regular computer monitor. Bottom right is where the two 1000BASE-T Ethernet jacks are located. Just to the left of that is the integrated power supply, with its own fan, IEC receptacle and power switch integrated into the rear panel. The main cooling fan is in the middle left, keeping both the drives and the electronics cool. I didn't see a spot for a Kensington lock hole.

There are ventilation holes on the sides, bottom, and rear of the Thecus N5550 chassis. The primary entry point for cool air is through the front of the drive trays; it passes over the HDDs and is then exhausted out the rear of the unit. The additional holes in the side panels help to balance the flow, especially if you let dust build up on the mesh front panel. I've yet to use a NAS that had effective filtering, but I guess the mesh on the front door does help catch some dust. In order to keep things cool when needed and quiet the rest of the time, the fan speed is modulated. I haven't paid much attention to fan noise in most of the smaller NAS models I've reviewed, as it was never really noticeable during my daily use. The Thecus N5550 continued that pattern, blending in to the background noise of my study, despite having two cooling fans exhausting out its rear panel.

The bottom of the Thecus N5550 is a simple affair with four composite feet, a few more ventilation holes to feed fresh air to the power supply, and a product label with Model and Serial numbers. All of the feet had slipped sideways a bit, as the adhesive holding them in place had loosened somehow. The unit was not subjected to any high heat conditions, but the power supply is located on the bottom, so maybe the heat was internally generated. The feet are pretty low profile, so there is normally not a lot of room below the bottom panel and I may have pushed the unit sideways when trying to lift it a couple times.

Now that we've had a thorough tour of the exterior, let's do a complete tear-down and see what the insides look like. The next section covers Insider Details.

Insider Details: Thecus N5550 NAS Server

The insides of these things are always more interesting than the outsides, at least to me. The N5550 comes apart very quickly and easily, with just three captive screws to be released on the rear panel. Once they're loosened, the outer shell slides off the front, revealing all the internal parts. Further disassembly requires a nutdriver or two, to remove the jack screws from the VGA D-Sub connector and to remove the power supply from the rear panel. The main controller board takes up the entire left side of the unit, and nearly everything is integrated on the one board, including all the front and back panel connectors. The two exceptions are the backplane where all the SATA connections for the drives are mounted, and the LED display and menu buttons from the front panel, which connect via ribbon cable. The main controller PC board slides into the plastic channels chassis at the top and bottom of the inner chassis. The board is not held in place by screws, but is captured so that it has no room to move.

Once you remove those couple of screws holding the rest of the chassis together, it comes apart in several smaller pieces. Most of the metalwork is permanently fastened together, or formed from a single sheet, so there are fewer loose components than I've seen on other NAS products. One design feature I was very impressed by was the bonding of the backplane PCB to a metal backing plate. The resulting sandwich is very stiff, which is exactly what you want for a backplane that has 1 kg HDDs occasionally slamming into it. The inner framework is a solid sheet metal assembly that is riveted together so that it stays dimensionally stable. The integrated power supply slides in from the rear and is held in place with four screws. The electrical output looks to be standard ATX connectors, which makes sense once you figure out just how close the overall architecture of this NAS is to a regular PC.

The main controller board is densely populated, not as much as a high performance video card, but the majority of the parts on the N5550 board are there to provide a unique set of functions. A video card PCB has at least 25% of the surface consumed by power regulation and distribution hardware. The main controller board and backplane connect with an x16 PCI Express connector located toward the rear of the controller card, between the CPU and the stacked I/O connectors. Noticeably absent from the main controller card is a power connector; all the electrical current comes through the PCI Express connector via the backplane PCB. Most of the current goes out to the hard drives, so it makes sense to land the power supply cables directly to that board, instead of here. The two passively cooled heatsinks cover the main chips supplied by Intel, the Dual-Core D2550 Atom CPU, and the ICH10R Southbridge that provides the SATA connections and the RAID logic. These two ICs do the bulk of the work for this NAS device; the only other chips that are even moderately stressed are the memory and the Ethernet controller.

The limited cooling required for the two hardest working chips on the controller board is made even more obvious once you remove the heatsink and see the type of thermal interface materials in use. The ICH10R Southbridge is thermally connected to the heatsink with that hard, plasticky material that we used to see on low-end video cards in the '80s and '90s. At least the assembly process and the viscosity of the material worked together to produce a thin interface layer. That's better than a 1mm thick layer of the good stuff, perhaps.

Speaking of cooling - I know I mentioned the fan before, but here it is mounted to the rear panel with the traditional, stubby, thread-forming screws that 90% of PC case fans are fastened with. It's a standard 92mm case fan, with 3-wire tachometer control and is modulated by the controller card. It was quiet and unobtrusive the entire time I had the unit under test, to the point where I never really paid any attention to it.

So far we've had a good look at what there is to observe as far as hardware goes, but let's dig down one more layer, down to the chip level where the technology really starts to get interesting. I love my shiny hardware just as much as the next person, but it's only half the story....

Technology Details: Thecus N5550 NAS Server

The N5550 uses one of the most recently released Intel Atom Dual-Core CPUs based on 32nm fabrication technology, the D2550. Introduced in March of 2012, the D2550 is a cross between the D2500 and D2700 processors, operating at the lower clock frequency of 1.86 GHz, but supporting Hyper-Threading on its two physical cores. The integrated graphics controller runs at the faster clock speed of 640 MHz, which normally wouldn't be important for a NAS, but Thecus allows direct streaming of HD video from the N5550, so it does come in handy. Lastly, the 1MB Intel Smart Cache and the integrated memory controller that supports DDR3-1066 DRAM are both performance enhancing features that are at the forefront of what's available in low power computing these days. With the D2700 going EOL in September of this year, the D2550 is the crown prince of the Atom family at the moment.

The biggest chip on the board is actually not the CPU, it's the SATA interface/ RAID controller chip. Thecus surprised me by using a SATA controller that's ubiquitous in the PC world, but almost never heard from in the NAS environment. Intel's ICH10R is perhaps one of the most widely used RAID controllers in x86 PCs, just because it was attached as the Southbridge to several generations of high-end Intel CPUs since it debuted in 2008. Short of doing a full blown custom ASIC, it's hard to beat the performance of this mainstream solution, which was developed back when the most common way of increasing disk throughput was to RAID several HDDs together. Today's Southbridges (err.... Platform Hub Controllers) are rightly judged more by their ability to squeeze the utmost performance out of the latest SSDs, but the ICH10R served admirably during the transition period between high speed spindles and flash memory. There is a widespread understanding that the ICH10R has an upper limit of about 660 MB/s on its aggregate of SATA interfaces, but that's of no importance when the system's I/O bandwidth is constrained by a pair of Gigabit Ethernet ports on the back panel of the NAS.

The Thecus N5550 is unusual in its support for dedicated display outputs that are driven entirely by the NAS. Intel recently released a new 64-bit driver for multimedia support, and Thecus followed it up with a new Local Display software module that allows direct connection from the NAS to HDTV. It's a real bonus for both administration tasks, and for supporting streaming video and other multimedia, if you decide to use it for content delivery in addition to storage. In order to do that, some extra chips are needed that you typically don't see deployed on a NAS. The Chrontel CH7318C is a high speed HDMI level shifter that converts low-swing AC coupled differential input to an HDMI 1.3 compliant output. The Intel Atom D2550 has an Intel Graphics Media Accelerator 3650 integrated on it that can handle dual displays, but still needs the extra chip to handle HDMI. Despite the graphical inference in the firm's name, the Silicon Image Sil3132 chip just provides an interface from 1x PCIe on the ICH10R Southbridge to the single eSATA port on the rear panel. The Sil3132 supports two eSATA ports, so future models may support dual eSATA connections.

The two Gigabit Ethernet controllers are supplied by Intel and they incorporate both Media Access Control (MAC) and a Physical Layer (PHY) port. Each WG82574L chip supports one Ethernet jack on the rear panel, and connects to the rest of the system by an x1 PCIe Rev. 1.1 interface. There is a 40kB buffer on-board to smooth out data transfers by buffering complete packets before transmitting them. Intel is one of the premier suppliers of NICs to the enterprise market, so it's not a big surprise that many NAS vendors tend to choose their products for implementing integrated GbE interfaces. Renesas Electronics (nee NEC) provides their ubiquitous D720200F1 chip for USB 3.0 duties. I can't remember the last time I saw any other chip being used for USB 3.0. Sound duties are supported by a Realtek ALC262, a basic soundcard chip that doesn't have a whole lot to do here, except when using the NAS as a multimedia streaming device. Only 2-channel audio is supported here, nothing like 5.1 or 7.1 is available, if you need the full home theater experience.

2 GB of DDR3-1066 memory is standard on the Thecus N5550; it's carried on the SO-DIMM form factor and is addressed by the CPU in Single-Channel mode. The Atom D2550 CPU can support up to 4 GB of DRAM, but it's unclear if the N5550 can support a memory upgrade or not. There are two SO-DIMM sockets on the motherboard and only one module supplied, but the BIOS is the key as to whether an upgrade will work or not. The single SO-DIMM in my sample was supplied by Transcend and is rated for DDR3-1333 with timings of 9-9-9 for CL-tRCD-tRP. The eight SDRAM chips themselves are from SpecTek, which is a division of Micron Technology.

Last, but not least is the Flash memory implemented as a Disk-On-Module (DOM) device, which is 1 GB of SLC-based NAND sourced from local Taiwanese manufacturer Afaya. Serving up a Linux-based operating system to a 1.86 GHz Atom CPU is the dog's life for a flash memory chip; this module never breaks a sweat. Right next to the DOM location is an empty mini-PCI Express slot. No word from Thecus on what it's typically used for, but the most common devices available in that form factor are SSD modules and wireless Ethernet cards. I'd love to see something similar to Intel's Smart Response Technology implemented in a NAS; that's something that more and more high-end storage vendors are starting to roll out in their data center-class storage systems. Virtualized server infrastructures are pushing the storage systems harder and harder, every year. OTOH, a Wi-Fi module is a whole lot easier to implement on this Intel Atom platform, so that's probably what this slot will get used for, first.

To measure isolated NAS power consumption, Benchmark Reviews uses the Kill-A-Watt EZ (model P4460) power meter made by P3 International. Obviously, power consumption is going to depend heavily on the number and type of drives that are installed. The power draw also depends on the fan speed that's required to keep the drives cool. When the Thecus N5550 first boots up, it peaked briefly at 120 W, and then ramped down to a narrow range of 48 W to 54 W. Once the system completes its boot process, and gets into normal operating mode, it settled in at about 53 watts of power consumption. With all four drives installed and during Write operations, it drew 58W; Read operations drew hardly more than idle. When the ½ hour sleep timer kicked in and the drives were powered down, the power consumption went down to 33W. When the unit is turned off, it still consumes 2W in Vampire mode; be aware that even when it's turned off, the integral 200W SMPS still pulls a small amount of power.

We've seen the ins and outs of the hardware, and the technology under the hood; now let's take a quick look through the list of features that you get with the Thecus N5550. The next couple of sections are kind of long, but it's critical to understand what features you get with these units, and what you don't. It's not just a box full of drives; it's capable of more than that.

Thecus N5550 NAS Server Features

As the volume of personal and business data continue to rise exponentially, the systems we use to store and manage it have become more complex. I started my long relationship with computers when program storage meant a shoebox full of punch cards. Now, a bare-bones PC starts off with almost a million files on it BEFORE you add your own data. I'm not going to tell you that computing is going to get any simpler, that's an outright lie, but I can say that the tools we use to manage them are going to make it easier. Thecus has introduced several new features with the N5550 that make it stand out from the NAS crowd. We'll look at the newest and most unique features first, and then cover some of the more common ones.

Antivirus Powered by McAfee

The Thecus N550 ships with a custom version of McAfee that protects the NAS from threats on the network. This feature is long overdue in the NAS marketplace, IMHO. Anyone who allows unprotected computers to run on their network better have some strong defenses built into the network infrastructure, or they risk quick and certain infection. The older NAS products were somewhat immune, because of their proprietary hardware and software, but modern NAS devices are using more common and vulnerable architectures. The silver lining in this shift towards more mainstream components is that mainstream security products can be leveraged, which is exactly what Thecus has done.

High Definition Media Output

For years, I've seen video connections on the rear panels of NAS units, and then been disappointed when I read in the manual that it was only for use in "Maintenance" mode, in most cases only accessible by factory technicians. Thecus has finally opened up the video port for use by the general user! It's not just for system setup anymore, either. The HDMI (or VGA) output can be used for web browsing and HD video playback as well. The Intel D2550 Atom CPU in the Thecus N5550 supports dual displays with its GMA 3650 integrated graphics processors, running at 650 MHz in this implimentation.

Data Burn

There are times when you just need to pull some data off the network and put it into cold storage, or maybe you need to distribute multiple copies. Either way, sometimes you want to hook up a DVD or Blu-ray burner directly to the NAS and burn some disks. Now you can do that, because the disk burning software is built into the NAS. In the past, you had to access the NAS from a workstation with disk burning H/W and S/W installed on it. With the new Data Burn utility, you can use the direct KVM interface to the N5550 or connect through a browser window on any PC that's on the network.

USB 3.0 Connection

Once you're used to Gigabit transfer speeds with your NAS, the thin trickle of DATA that passes through USB 2.0 becomes a painful experience. USB comes to the rescue on the Thecus N5550, with a max data rate that's 10x faster than the previous USB standard. Theoretical throughput is up to 5Gb/s, but there aren't any USB devices I know of that will actually provide that kind of speed. There is only one USB 3.0 port on the N5550, and it's located on the front panel, behind the door. That could little inconvenient, if you are planning to use an external USB drive to make backups, OTOH, if you're moving those backups off-site then you won't mind plugging the device into the front of the N5550.

Selectable File System

NAS users have been using ext3 and ext4 file systems for a while now. Since most NAS devices are running a Linux O/S, it makes sense that vendors are now offering XFS as an option. Introduced in 1994 by Silicon Graphics and inserted in the Linux kernel in 2002, it's now common in almost all Linux-based systems. Scalability with highly parallel I/O activity is its strongest attribute, and Thecus sees a place for it in NAS appliances. Once you look at the depth of the Thecus product line, towards the data center environment, this addition makes a lot more sense.

Cloud Backup

Despite the fact that a well-connected NAS functions an awful lot like a private cloud, all the NAS vendors want to make sure that their NAS users have access to one or more public cloud applications. Thecus teams up with Dropbox, ElephantDrive, Amazon S3, and Acronis (via module), to allow the N5550 to perform regular backups from the NAS to the public cloud storage provider chosen by the user. This is becoming much more mainstream than it was a couple years ago, and it's a much simpler way of generating off-site backups than almost any other method. It's a whole lot easier than convincing a friend or family memeber to host your backups on their network, and a lot more secure, as well.

Mobile Applications (IOS & Android)

Thecus has two applications that run on mobile devices and connect back into the NAS on your network. One of them is Thecus Dashboard, and it's used for remote monitoring and control of the NAS. I tend to set these up and then like to forget about administering them, but not everyone has that luxury. Corporate NAS administrators are expected to be on duty 24/7/365, and this is one reason why. The second application is called ThecusShare^TM and it is used for uploading, downloading and streaming media files to and from your mobile device. I see this application getting much more attention from most users who are in the market for a NAS unit like the Thecus N5550. After all, you don't want to put ALL your vacation photos on Facebook, do you?

Now that we've loooked at the most significant features of the Thecus N5550, let's look at the Hardware and Software specifications that provide the power and performance to make those features run.

Thecus N5550 Hardware Specifications

Hardware Specifications

Thecus N5550 Software Specifications

The Thecus N5550 is designed for home use and small businesses. Nowadays, the typical home environment looks very similar to a small business anyways. When you have to combine the latest high tech devices, the legacy hardware and applications that everyone still has hanging around, the need to grant granular access to multiple terabytes of data with varying sensitivity, unified communications, and peripheral sharing - it's a daunting challenge. I also challenge you to tell me whether that last sentence refers to a small business or your own home network.

Because the Thecus NAS software is common across the product line, there are a great number of software features included with the N5550 that the typical user will never use, never see, and never even know they exist. You can be sure though, that every corporate sys/admin is looking through this list of software capabilities and checking off the required boxes for deploying a NAS in a secure large-scale business environment.

Software Specifications

Besides the core features available in the Thecus firmware, additional capabilities are available in the form of add-in Modules. I counted twenty on the Thecus Website, and here's a summary list. In addition to the factory modules, there is a public element in play. Most of the third party modules are captured in the Thecus Forum.

• Access Guard module
• Dashboard Module
• Dropbox module
• ElephantDrive module
• HiSSH module
• IP CAM module
• Local Display module
• Mail server module
• MySQL module
• NZB module
• Piczza! module
• Raid Replication Module
• Rsync backup module
• T-OnTheGo and Transcoding service Module
• Transmission (BT Client) Module
• Twonky media server module
• USB & eSATA schedule backup module
• VirusScan module (McAfee Antivirus )
• Web Server module
• WebDisk module

Thecus N5550 NAS Server Setup & Usage

The first thing you need to do with most NAS devices is discover them on your network and set them up. Most NAS vendors bundle a small, lightweight "finder" application with their products that has some system utilities included. The Thecus Setup Wizard provides Device Discovery, System Login, Network Configuration, and Password maintenance, all before you log in to the full monitoring & control applications via the web browser. There are a number of sub-menus that you go through during initial setup; once you do that, the setup wizard is still available in case you get forget your password or need to reconfigure the NAS. Otherwise, just use your browser and login to the IP address that the NAS is configured to; the default is 192.168.1.100.

Once the initial setup is complete, you need to log in to the main admin application, which Thecus calls the Web Administration Interface. The areas you can control are divided up into the following groups:

• System Information
• System Management
• System Network
• Storage
• User & Group Authentication
• Network Services
• Application Server
• Module Management
• Backup
• External Devices

Each of these menu items is broken down further, as you can see below. If you read through the entire Software Features section, then the number of sub-menus should not be a surprise for you.

One of the critical aspects of setting up a NAS is the networking configuration. It's so easy to get it wrong and accidentally shut down access, that Thecus includes tools in their setup wizard application, which you can still access after you inadvertently locked yourself out. If you get it completely out of whack, it's still possible to recover by using the system reset function, which can be accessed with the front panel buttons in tandem with the LCD display. Don't ask me how I know this to be true... Once you're inside, this screen lets you change global settings and individual settings for each of the Ethernet ports available on the system. Manual and DHCP setting of port addresses is allowed, and I ended up setting static IP addresses for this NAS, so that I didn't have to run the data through a network switch. IPv4 and IPv6 are both accommodated and a default port can be selected. The two integral ports on the N5550are labeled "WAN/LAN1" and "LAN2"; no other ports will be listed since there is no expansion slot available for additional NICs.

A separate Link Aggregation tab allows two or more ports to be linked together and configured for a variety of protocols: Load balance, Failover, Balance-XOR, Broadcast, 802.3ad, Balance-TLB, or Balance-ALB. The two ports on the N5550 are easily linked and unlinked, by using these tools. All testing in this review was done with single port connections, to keep the playing field level. I have had very mixed results so far using LACP on a variety of NAS products; it's not a simple plug-and-play way to double your throughput, that's for sure.

The Disk Information screen provides detailed information on the disks installed, including their SMART information. It's an easy way to see if one drive is getting hotter than the rest, for some reason. Whatever the reason, it's usually the first step in detecting bearing or motor failure. If you dig down one more layer you can get information on the disk's Reallocated Sector Count and Current Pending Sector Count. These metrics tell you the real story on how bad blocks are affecting your disk operations. As more bad blocks get hidden away in reallocated sectors, more sectors are removed from service and read/write performance is slowly degraded. This screen also shows the type of hard disk interface in use and the link speed. Normally, this information should be obvious, but in some cases a jumper on the HDD may be installed wrong and the drive could be operating at a lower link speed. This also a convenient place to see what firmware is installed on each of the HDDs.

The detailed system log is where you go to see what's REALLY going on with the system. It's also a good place to look every now and then to make sure your automated backup jobs are running correctly. The log tells all...! There's a download button, if you want to keep copies in another location, or just want to share your logs with others on Facebook. You can also clear the log, which is labeled Truncate All Log Files on the menu.

Let's look at the RAID expansion and Migration process a little. I started with a single drive and the way the N5550 treated that was to call it a JBOD configuration. That seems counterintuitive to me, since there was only one disk, but it's just another way of saying that all disks physically installed in the NAS will be treated as individual disk volumes. Next, I needed to install three additional disks and configure them as RAID 5. There is no way to migrate from a JBOD setup to a RAID volume, the data stored on the JBOD disks has to be deleted. Not a problem for me, and most users won't need to follow this path, but it's something to be aware of. So I deleted the existing volume and started the RAID Volume Creation process. One of the options Thecus offers is Quick RAID, which shortens the RAID creation time if you are using drives that have not been partitioned. I was re-using drives that had previously been installed in another NAS, so I couldn't use this option. I opted to create the RAID 5 volume in one shot, and it was very straightforward. Because I had four drives installed I had several options, including RAID 6 or the use of a hot spare with RAID 5.

Ok, if you've been following along this far, there's not much more I can show you except how fast it is. So let's get down to some benchmarking, and compare it to a variety of other NAS products that we've looked at in the recent past.

Network Terminology

Benchmark Reviews primarily uses metric data measurement for testing storage products, for anyone who is interested in learning the relevant history of this sore spot in the industry, I've included a small explanation below:

The basic unit data measurement is called a bit (one single binary digit). Computers use these bits, which are composed of ones and zeros, to communicate their contents. All files are stored as binary files, and translated into working files by the Operating System. This two number system is called a "binary number system". In comparison, the decimal number system has ten unique digits consisting of zero through nine. Essentially it boils down to differences between binary and metric measurements, because testing is deeply impacted without carefully separating the two. For example, the difference between the transfer time of a one-Gigabyte (1000 Megabytes) file is going to be significantly better than a true binary Gigabyte (referred to as a Gibibyte) that contains 1024 Megabytes. The larger the file used for data transfer, the bigger the difference will be.

Have you ever wondered why your 500 GB hard drive only has about 488 GB once it has been formatted? Most Operating Systems utilize the binary number system to express file data size, however the prefixes for the multiples are based on the metric system. So even though a metric "Kilo" equals 1,000, a binary "Kilo" equals 1,024. Are you confused yet? Don't be surprised, because even the most tech savvy people often mistake the two. Plainly put, the Kilobyte is expressed as 1000 bytes, but it is really comprised of 1,024 bytes.

Most network engineers are not fully aware that the IEC changed the way we calculate and name data chunks when they published the new International Standards back in December 1998. The International Electrotechnical Commission (IEC) removed the old metric prefixes for multiples in binary code with new prefixes for binary multiples made up of only the first two letters of the metric prefixes and adding the first two letters of the word "binary". For example, instead of Megabyte (MB) or Gigabyte (GB), the new terms would be Mebibyte (MiB) or Gibibyte (GiB). While this is the new official IEC International Standard, it has not been widely adopted yet because it is either still unknown by institutions or not commonly used.

NAS Testing Methodology

All the NAS devices we test cannot accommodate all the different disk configurations, so our current test protocol has been based on two of the most popular setups: a basic (single) disk and RAID-5 configurations. Most NAS products that can support RAID 5 go beyond the minimum number of drive bays, to a total of four, so that is the number of drives that I typically use to test with, even though I could get by with only three. During initial setup, the NAS was tested for the latest firmware by checking the Thecus website The firmware installed on the N5550 was v2.02.05 when I received it, which is the most current version.

Normally, I connect the NAS directly to an Intel Gigabit CT Desktop LAN controller in the test-bench system, with ten-foot CAT6 patch cables. This time, the NAS wasn't being recognized until I set up a static IP address of 192.168.168.xxx on the host PC. The N5550 absolutely has to be on the same subnet as the host, or it will not be seen. I did a couple quick throughput tests and saw no appreciable difference, so I went with a more realistic network arrangement and plugged the Thecus into the local GbE switch that I normally connect all my test systems to. At the transfer speeds I was seeing, the single GbE connection wasn't holding the unit back, so I used that setup for all the testing.

With the networking taken care of, the next potential bottleneck that needed attention is the disk system on the host PC. In previous tests, I relied on the third generation OCZ Agility SSD, which is good for at least 500 MB/s, input or output, on the appropriate Intel Platform Controller Hub. While I was doing some testing with an 8-bay monster NAS and 10GbE connections, I decided it was time to bypass the SSD on the test rig and install a RAM Disk. There are at least a dozen products on the market that will create and manage a RAM Disk on Windows systems; I chose RAMDisk v3.5.1.130R22 from Dataram based on performance tests in several reviews (we read 'em, too....) and its reasonable cost structure. I needed to assign at least 10GB of space to the RAM Disk, in order to replicate the test protocol I've been using for all my NAS testing, so none of the freeware products looked suitable. One other trick was necessary, to get the RAM Disk to transfer files larger than 2GB, I had to use the "Convert" utility in Windows to make the RAM Disk into an NTFS volume. Then I was able to perform the file transfers with 10GB files, no problem. If you want to avoid this extra step, be sure to look for a RAM Disk product that directly supports the NTFS file system.

For basic throughput evaluation, the NAS product received one test transfer followed by at least three timed transfers. Each test file was sent to the Western Digital Caviar Black 750GB (WD7502AAEX) hard drives installed in the NAS for a timed NAS write test, and that same file was sent back to the RAM Disk in the test system to perform a NAS read test. Each test was repeated several times, the high and low values were discarded and the average of the remaining results was recorded and charted.

The Read and Write transfer tests were conducted on each NAS appliance using the 1 GB file and then a 10 GB file. A second set of tests are conducted with Jumbo Frame enabled, i.e. the MTU value for all the Ethernet controllers is increased from 1500 to 9000. Most of the NAS products tested to date in the Windows 7 environment have supported the Jumbo Frame configuration. Only the NETGEAR ReadyNAS NV+ v2 uses the 1500 MTU setting by default, and has no user-accessible controls to change that; you'll see that reflected in the charts. I used a single GbE for all tests; I have not been able to achieve consistent results with various units using the IEEE 802.3ad Link Aggregation Control Protocol (LACP) mode.

I also ran the Intel NAS Performance Toolkit (NASPT) version 1.7.1, which was originally designed to run on a Windows XP client. People smarter than me have figured out how to run it under Windows 7, including the 64-bit version that is used more often than the 32-bit version these days. NASPT brings an important perspective to our test protocol, as it is designed to measure the performance of a NAS system as viewed from the end user's perspective. Benchmarks like ATTO use Direct I/O Access to accurately measure disk performance with minimal influence from the OS and the host platform. This provides important, objective data that can be used to measure raw, physical performance. While it's critical to measure the base performance, it's also important to quantify what you can expect using real-world applications, and that's exactly what NASPT does. One of the disadvantages of NASPT is that it is influenced by the amount of memory installed on the client, and it was designed for systems that had 2-4 GB of RAM. Consequently, two of the tests give unrealistic results, because they are measuring the speed of the buffer on the client, instead of the actual NAS performance. For that reason, we will ignore the results for "HD Video Record" and "File Copy to NAS". I'm also not going to pay too much attention to the "Content Creation" test, as it is too heavily focused on computing tasks that aren't really handled by the NAS.

Benchmark Reviews was also able to measures NAS performance using some tests that are traditionally used for internal drives. The ATTO Disk Benchmark program is free, and offers a comprehensive set of test variables to work with. In terms of disk performance, it measures interface transfer rates at various intervals for a user-specified length and then reports read and write speeds for these spot-tests. CrystalDiskMark 3.0 is a file transfer and operational bandwidth benchmark tool from Crystal Dew World that offers performance transfer speed results using sequential, 512KB random, and 4KB random samples. Benchmark Reviews uses CrystalDiskMark to illustrate operational IOPS performance with multiple threads, which allows us to determine operational bandwidth under heavy load.

We are continuing our NAS testing with the exclusive use of Windows 7 as the testing platform for the host system. The performance differences between Win7 and XP are huge, as we documented in our QNAP TS-259 Pro review. The adoption rate for Win 7 has been very high, and Benchmark Reviews has been using Win 7 in all of our other testing for some time now. It was definitely time to make the jump for NAS products.

NAS Comparison Products

• Thecus N5550 4-Bay SATA NAS Server
• Netgear ReadyNAS NV+ v2 Gigabit 4-bay SATA NAS Server
• QNAP TS-879U-RP Gigabit 8-bay SATA NAS Server
• QNAP TS-219P+ Gigabit 2-Bay SATA NAS server
• QNAP TS-259 Pro Gigabit 2-Bay SATA NAS server
• QNAP TS-659 Pro II Gigabit 6-Bay SATA NAS server
• QNAP TS-419P II Gigabit 4-bay SATA NAS Server

Support Equipment

• (4) Western Digital Caviar Black WD7502AAEX 750GB 7200 RPM 64MB Cache SATA 6.0Gb/s 3.5"
• Intel EXPI9301 CT Gigabit Ethernet NIC, x1 PCIe 1.1, 1x CAT5
• Trendnet 8-port GbE Switch TEG-S80g
• Dataram RAMDisk v3.5.1.130R22
• Intel NAS Performance Toolkit (NASPT) version 1.7.1
• ATTO Disk Benchmark v2.47
• CrystalDiskMark 3.0
• 10-Foot Category-6 Solid Copper Shielded Twisted Pair Patch Cable
• 1 metric Gigabyte Test File (1 GB = 1,000,000,000 bytes)
• 10 metric Gigabyte Test File (10 GB = 10,000,000,000 bytes)
  

Test System

• Motherboard: MSI Z68-Express Z68A-GD80 (1.23.1108 BIOS)
• System Memory: 4x 4GB Corsair Vengeance LP DDR3 1600MHz (9-9-9-24)
• Processor: Intel Core i5-2500K Sandy Bridge 3.3GHz (BX80623I52500K)
• CPU Cooler: Thermalright Venomous-X (Delta AFB1212SHE PWM Fan)
• Video: Intel HD Graphics 3000
• Drive 1: OCZ Agility3 SSD 120GB (AGT3-25SAT3-120G)
• Optical Drive: Sony NEC Optiarc DVD (AD-7190A-OB 20X)
• Enclosure: Lian Li Armorsuit PC-P50R
• PSU: Corsair CMPSU-750TX ATX12V V2.2 750Watt
• Monitor: SOYO 24"; Widescreen LCD Monitor (DYLM24E6) 1920X1200
• Operating System: Windows 7 Ultimate Version 6.1 (Build 7600)

1GB Single-Disk Test Results

The bottom line for any storage device is the combination of capacity and transfer speed. For a network attached storage server, the differences are all about the infrastructure that is placed around the basic HDD array. Since capacity is something that's easy to define and measure, the real question for any NAS product is how fast will it Read and Write data. For this reason, Benchmark Reviews primarily measures NAS performance as the bandwidth achieved during a file transfer test. The first tests we perform utilize a single 1GB (1000 megabytes / 1,000,000,000 bytes) file in a transfer to and from the NAS.

With all the NAS units operating in single disk mode, many of the units have broadly similar performance. The differences are mostly down to CPU performance in this test, although some of the other infrastructure ICs do have an impact. The TS-879U-RP tops the 1 GB Read tests, primarily due to its Intel Core i3 CPU, which is much more powerful than any of the other CPUs in play here. The rest of the QNAP units run in the mid-80 MB/s range, with not much difference between Atom-based and Marvell-based models. The Thecus N5550 slots in between the TS-879U-RP and the rest, with excellent Read results of 105.4 MB/s with Jumbo Frames enabled on the networking side. The Read results for the N5550 with an MTU value of 1500 are only slightly behind, at 102.7 MB/s. Most people who buy a 4-bay NAS don't care too much about single disk performance, but it's useful to get an understanding of any possible issues with the basic architecture of the system. It definitely looks like the N5550 architecture can hold its own in Read performance; let's look at Write performance next.

Moving on to the 1 GB write bandwidth test, there is a more linear pattern to our results, with infrastructure and processing power having what looks like a bigger influence than it did in the Read test. The QNAP TS-879U-RP posts the top numbers again, and the write speeds of the other models follow along with the pricing of the units and the processing power of their installed CPU. In general, the Intel Atom-based models are performing better than the Marvell-based units with the weaker CPUs, but the Thecus N5550 gets a little extra performance boost from within. The N5550 achieves a 113.2/117.2 MB/s write speed with a single 750GB disk installed, using the JBOD disk management protocol. That's class-leading performance, as you can see for yourself.

Next up is 10 GB (1000 metric megabytes / 10,000,000,000 bytes) file transfer testing. Using the single-disk configuration in each NAS, and a Gigabit Ethernet connection, network throughput will be put to the test, and the effect of any system or hardware caches will be minimized.

10GB Single-Disk Test Results

Examining 10GB basic file transfer speeds, the mid-range QNAP models all got a boost, compared to the 1 GB file transfers. Their read speed went up by approximately 10 MB/s, to a combined average of 95 MB/s. The TS-879U-RP delivered similar read performance with the two file sizes, and the Thecus N5550 picked up a few extra MB/s. Clearly none of these units were bothered by handling very large files. Later in our testing, we will look at some other NAS test protocols that feature small file sizes, which is a common situation for backup applications. Once again, you get none of the advantages of redundancy with a single disk or JBOD configuration, and most NAS users will go for one of the RAID configurations. These figures are not precisely what the average user will experience; those will be seen later in our RAID 5 tests.

In our 10GB write performance tests, the performance of all the NAS units is similar to their showing with the smaller sized, 1 GB file. The Thecus N5550 hits almost the exact same performance level, at 113.6/118.2 MB/s with 1500 and 9000 MTU values. What's really impressive here is the performance compared to the QNAP TS-659 Pro II, which is running a dual core Intel Atom D525 at 1.8 GHz. That's a very powerful processor by NAS standards, and the Thecus still beats it by a considerable margin.

Next we're going to look at RAID 5 performance, where the Thecus N5550 will have to compete with some heavy-duty challengers in the QNAP product line. Since the QNAP TS-259 Pro and TS-219P+ don't support the RAID5 configuration that we normally use to test large format NAS products, we won't be including their results in this next comparison.

NAS Comparison Products

• Thecus N5550 4-Bay SATA NAS Server
• Netgear ReadyNAS NV+ v2 Gigabit 4-bay SATA NAS Server
• QNAP TS-879U-RP Gigabit 8-bay SATA NAS Server
• QNAP TS-219P+ Gigabit 2-Bay SATA NAS server
• QNAP TS-259 Pro Gigabit 2-Bay SATA NAS server
• QNAP TS-659 Pro II Gigabit 6-Bay SATA NAS server
• QNAP TS-419P II Gigabit 4-bay SATA NAS Server

1GB RAID 5 Test Results

If you've got more than three HDD spindle to put in play, it makes sense to use one of the more advanced RAID configurations. RAID 5 is one of the most popular setups, primarily due to the balance it exhibits between capacity and redundancy. Not surprisingly, most NAS units that can support more than three HDDs also support RAID 5, so it makes sense to use it for test purposes. Most NAS products that can support RAID 5 go beyond the minimum number of drive bays, to a total of four, so that is the number of drives that I typically use to test with, even though I could get by with only three. The Thecus N5550 has five bays, which could offer increased performance over a four-bay system, but we want to test comparable configurations here. Even the 8-bay QNAP TS-879U-RP is tested with the standard four disk contingent.

The results for RAID 5 Read testing show the Thecus N5550 running neck-and-neck with the more costly QNAP TS-879U-RP, racking up a 109.8 MB/s average read speed with 1 GB files. That's quite a feat, as the mighty TS-879U-RP uses its Intel Core i3 CPU to good advantage, and the Thecus does its thing with a Dual-Core Intel Atom. All of these NAS platforms do a credible job here, though. None of them would do a poor job in a typical READ scenario; it's typically the Write performance that separates the men from the not-so-men.

The 1 GB RAID 5 disk write test shows more clearly the strain that this particular RAID configuration puts on the NAS infrastructure. It's well known that RAID 5 write performance can be a weak point, with all the computation overhead involved and the extra parity bits that need to be calculated and written to each of the drives. The only way to overcome that is with raw computational horsepower, which is why the ARM-based models lag behind both the Intel Atom and Core i3 units. The Thecus N5550 puts in a stellar second-place performance, reaching an average write speed of 111.5 MB/s compared to the 116.2 MB/s of the QNAP TS-879U-RP. That's a good jump up from the TS-659 Pro II which gets 97.4 MB/s out of the same four disks. The Marvell-based NAS devices just can't compete at the same level here. It's an inescapable fact that the simplest assignment any NAS can perform is basic backup duty, and in order to do that task well, you need to buy the most powerful system to effectively reap the benefits of a multi-disk array. Don't scrimp on the NAS platform if you can help it.

Next up is 10 GB (1000 metric megabytes / 10,000,000,000 bytes) file transfer testing. Using the 4-disk RAID 5 configuration in each NAS, and a single Gigabit connection, network throughput will be put to the test, and the effect of any system or hardware caches will be minimized.

10GB RAID 5 Test Results

Looking at read tests with a single 10GB file, the Thecus N5550 still hangs in there at the top of the performance ladder, with a read speed that's only 1.5% off from the highest performing unit. The results still favor the more expensive models, even though it's not a 1:1 ratio of improvement with higher cost. In order to do substantially better than this, you have to upgrade the network connection; GbE is only good for 125 MB/s, on a theoretical basis.

Looking at Write tests with a single 10GB file, the results are not all that different from the 1 GB tests. The Thecus N5550 runs at almost exactly the same average speed, in fact the Jumbo Frame results are identical. The same goes for the QNAP TS-879U-RP; the 9000 MTU write speed is the same, whether handling 1 GB files or 10 GB ones. The TS-879U-RP just laughs at the additional load of four hard drives; the CPU utilization never got above 25% during this test. The Thecus N5550 had to work a little harder, but the CPU load didn't get much higher than 50% during RAID 5 testing. The Marvell-based units always had the CPU maxed out in Write activity, and it really hurts the RAID performance.

All in all, my impression of these test results is that the Thecus N5550 is an excellent performer that exceeded my expectations. The marketing materials for this model have been a bit cagy about the CPU specifications, perhaps because Thecus thought people wouldn't believe the performance they achieved with an Atom Dual-Core. That's just speculation on my part, but the results surprised me quite a bit, especially Write performance. I'm a believer now, though.

NAS Comparison Products

• Thecus N5550 4-Bay SATA NAS Server
• Netgear ReadyNAS NV+ v2 Gigabit 4-bay SATA NAS Server
• QNAP TS-879U-RP Gigabit 8-bay SATA NAS Server
• QNAP TS-659 Pro II Gigabit 6-Bay SATA NAS server
• QNAP TS-419P II Gigabit 4-bay SATA NAS Server

Intel NASPT Test Results

NASPT brings an important perspective to our test protocol, as it is designed to measure the performance of a NAS system, as viewed from the end user's perspective. Benchmarks like ATTO use Direct I/O Access to accurately measure disk performance with minimal influence from the OS and the host platform. This provides important, objective data that can be used to measure raw, physical performance. While it's critical to measure the base performance, it's also important to quantify what you can expect using real-world applications, and that's exactly what NASPT does. In keeping with the real-world scenario, I only run these tests on the RAID 5 configurations, since that is what most users with a mid-size NAS are going to use. It just doesn't make sense to run realistic test scenarios on unrealistic hardware configurations.

One of the disadvantages of NASPT is that it is influenced by the amount of memory installed on the client, and it was designed for systems that had 2-4 GB of RAM. Consequently, two of the tests give unrealistic results with modern systems, because they are measuring the speed of the buffer on the client, instead of the actual NAS performance. For that reason, we will completely ignore the results for "HD Video Record" and "File Copy to NAS". Shown here is a batch run of 5 cycles through the tests, which turned out to be a bit slower than the individual runs. There seemed to be some wrinkles in the batch testing that don't show up on individual test runs, which is a bit of a pain, to be honest. The numbers in the chart below are an average of five separate runs, which I believe are more accurate than results from a consolidated batch run.

With a single, basic GbE interface in place, the results look somewhat similar to the first set of data I have from this test. No individual test gets very far past the ~ 120 MB/s theoretical barrier, but several of them are in the 70-90 MB/s range. Some of the tests have very low transfer rates, and that's due to the nature of the test. The Content Creation test for example, simulates a user creating a web page, accessing multiple sources for the content. The Directory Copy tests use several hundred directories and several thousand files to test a typical backup and restore scenario. That's one of the most real-world types of test, and it's useful for all of us to have a standard set of test data to use, because my directory of 1,000 random small files is never going to be the same as your directory of 1,000 random small files.

To summarize things, here are consolidated charts of the "Fast" NASPT tests, the "Medium-Speed" tests, and finally the "Slow" ones. First, the tests with relatively fast transfer rates. The Thecus N5550 aces all three of the HD Video Playback trials, improving its position as the speed of the playback increases. With 4x Video, the N5550 hits a high of 121.1 MB/s, which is close to the theoretical limit for a single GbE connection. At 1x playback, the QNAP TS-879U-RP squeezes out a lead of 3 MB/s, but the Thecus prevails convincingly at 2x and 4x. These units were all tested with a normal, GbE network connection, in order to eliminate network connectivity as a variable. Running the TS-879U-RP with one or more 10GbE interfaces would turn these tables upside down. Of course, that option is only available if you throw another couple of thousands of dollars towards the solution, so we'll continue to compare apples to apples here. The NETGEAR ReadyNAS NV+ v2 hangs on in third place, not too far back, which is good performance from that low cost platform.

The Medium-Speed tests are a bit of a mixed bag in the continuing rivalry between the TS-879U-RP and the Thecus N5550. The Thecus only pulls 66.4 MB/s on HD Playback & Record, well below the 87.6 MB/s of the QNAP. Things even out on the Office Productivity Suite test, and the N5550 comes in about 7% behind on the File Copy From NAS test. The NETGEAR ReadyNAS NV+ v2 hangs back a bit in third place, but stays within shouting distance on all three tests.

The "Slow" tests generally are slow because the file transfers are done with data sets that contain a bunch of small files of irregular size. In addition, the Directory Copy tests are accessing the file system index much more heavily than in the other tests. This adds a unique component that could be critically important for some users. The Directory Copy To NAS and Directory Copy From NAS results show a massive flip-flop on performance between the two top contenders here. The excellent Write performance provided by the TS-879U-RP system architecture gives a 74% advantage to the larger, 8-bay device when copying a large number of directories to the NAS. When copying those same directories out of the NAS, the Thecus N5550 beats the QNAP by 53%. I can't explain how or why there is such a reversal of fortune in the Directory Copy results, but this is a good demonstration of why it pays to look closely at your potential use cases when shopping for any H/W or S/W solution. The Photo Album test is a bunch of small files again, of varying sizes, arranged in a complex directory structure. This is a very common type of dataset, and these results show the N5550 providing excellent performance with this kind of data.

This was my third set of official tests with the Intel NASPT benchmarking tool, and I'm learning more about the meaning of the individual results every time. The DIR Copy results are a good example, where there was wide variation between platforms once pressure was put on the file system indexes. Most of the tests give predictable and meaningful results that represent real-world scenarios, so I'm continuing to use this benchmark, even if two or three of the test scenarios are not as useful.

NAS Comparison Products

• Thecus N5550 4-Bay SATA NAS Server
• Netgear ReadyNAS NV+ v2 Gigabit 4-bay SATA NAS Server
• QNAP TS-879U-RP Gigabit 8-bay SATA NAS Server

Non-Traditional NAS Test Results

In addition to measuring simple timed transfers, to determine how fast it will read and write contiguous blocks of data, Benchmark Reviews was also able to measures NAS performance using some tests that are traditionally used for internal drives. By mapping the Thecus N5550 as a local drive, some of our favorite HDD/SSD benchmarking tools worked just fine. Just like the NASPT test suite, I only run these tests on the RAID 5 configuration, as that is the most realistic scenario for a system like this. Some NAS products don't work too well with this type of test program; even though they may have the ability to map the NAS device to a drive letter, they're still not treated like local drives by the Operating System. I didn't have that problem with the Thecus N5550, so let's look at some results...

ATTO Disk Benchmark Results

The ATTO Disk Benchmark program is free, and offers a comprehensive set of test variables to work with. In terms of disk performance, it measures interface transfer rates at various intervals for a user-specified length and then reports read and write speeds for these spot-tests. There are some minor improvements made to the 2.46 version of the program that allow for test lengths up to 2GB, but all of our benchmarks are conducted with 256MB total length. ATTO Disk Benchmark requires that an active partition be set on the drive being tested. Please consider the results displayed by this benchmark to be basic bandwidth speed performance indicators.

The Thecus N5550 turned in a winning performance on ATTO, reaching a peak Read speed of 121.1 MB/s and a peak Write speed of 123.9 MB/s. These results are clearly in the very top tier of NAS performance, and a faster networking connection will be required in order to move beyond this level. With sequential performance like this powering the device, it's no wonder the Thecus N5550 does so well in some of the other, more structured test scenarios.

It's good to keep in mind that these ATTO tests are not always indicative of real-world performance, due to the sequential access mode used. In most cases, the results are going to be close to the numbers achieved in timed Read and Write tests. They are also going to be way above the results from some of the more challenging tests in the Intel NASPT suite. It's interesting to note that roughly 95% of the maximum performance level was reached by the 32 kB block size. That's a sign of good RAID management, and the high performance hard drives that are used in our testing.

CrystalDiskMark Results

CrystalDiskMark 3.0 is a file transfer and operational bandwidth benchmark tool from Crystal Dew World that offers performance transfer speed results using sequential, 512KB random, and 4KB random samples. For our test results chart below, the 4KB 32-Queue Depth read and write performance was measured using a 1000MB space. CrystalDiskMark requires that an active partition be set on the drive being tested. Benchmark Reviews uses CrystalDiskMark to illustrate operational IOPS performance with multiple threads. In addition to our other tests, this benchmark allows us to determine operational bandwidth under heavy load.

The combination of the Thecus N5550 and four Western Digital Caviar Black WD7502AAEX 7200 RPM 64MB Cache SATA 6.0Gb/s generates some excellent numbers in this test. It pulls a respectable 60.5 MB/s on sequential Read and outstanding 110.2 MB/s average on sequential Write tests. The 4k tests show very low numbers, but that's typical of HDDs, even in a RAID configuration. That's one of the huge advantages that SSDs bring to the table, is the ability to handle thousand of small data chunks very gracefully. But look at what happens when the Queue Depth is increased; this is usually a killer test for most storage systems, but the Thecus eats it up and asks for more.

All in all, these are a respectable set of results for Network Attached Storage. Sure, they're a bit lower than a true local drive connection, directly into the SATA controller on the motherboard. But, for a NAS device mimicking a local HDD, the Thecus N5550 performs very well.

NAS Server Final Thoughts

My first and solemn duty is to remind everyone that relying on a collection of drives in any RAID configuration for data backup purposes is a huge error. RAID systems provide protection against loss of services, not loss of data. Several examples will illustrate the problem, I hope:

• the drive controller goes bad and corrupts the data on all the drives in the array
• the entire storage device is physically or electrically damaged by external forces
• the entire storage device is lost, stolen, or destroyed
• a single drive in a RAID 5 cluster dies and during the rebuild process, which puts higher stress on the remaining drives, a second drive fails
• floods, earthquakes, tornadoes, etc. (AKA El Niño, Derecho)

All these points lead to the inescapable conclusion that multiple drives in a common system, in a single location do not provide effective and reliable data backup. Throughout this review I've talked about high-availability systems, and the Thecus N5550 fits that description well, especially when employed in a RAID 5 or RAID 6 configuration. With a single drive failure, your data is still available and accessible. The NAS device stays online the entire time while the failed drive is replaced and the array is rebuilt. That's what RAID systems are designed to do. The inherent redundancy is not meant to serve as a backup file set. Remember, we're not talking about losing data here, we're only talking about the ability to keep working uninterrupted, if one or two drives should fail.

If you look closely at the ATTO Disk Benchmark for the Thecus N5550 NAS Server, you see another benefit of such a system, even when straddled with obsolete GbE NICs. The full performance of the system is reached at the 32KB chunk size. That means that the system isn't just good at transferring data in a linear, sequential manner, it's good at handling smaller chunks of data too. Take a look at other system and see how well they handle smaller random chunks of data, compared to large sequential chunks, and you'll see how valuable this type of performance is.

In contrast to some Mega-NAS products I've tested recently, the Thecus N5550 is a product that most readers of Benchmark Reviews would probably contemplate purchasing. The cost of HDDs is coming down, although not to where they were before the Thailand floods, and the total storage needs of a modern household with all the latest high tech goodies is increasing rapidly. Although you can start with one disk and expand/migrate to RAID volumes later, I would recommend beginning with at least two drives, to get some data redundancy right away. Especially if you plan on using your NAS as front line storage, if you can avoid having to restore your data from backups, it's worth it.

The home and small business network is going to stay on Gigabit Ethernet for awhile. The cost to upgrade switches and routers to 10 GbE is still cost prohibitive for everyone who doesn't have a dedicated LAN room with a couple racks of equipment. If you're making that kind of investment in IT infrastructure, this article isn't for you. For the rest of us, this 5-bay GbE NAS is sitting right on top of the sweet spot for cost and performance. Its performance is top notch, and the price is reasonable.

So, what conclusions can we draw about this high performance, five-bay Thecus N5550 NAS server? Click NEXT to find out, and discuss...

Thecus N5550 Conclusion

Although the rating and final score mentioned in this conclusion are made to be as objective as possible, please be advised that every author perceives these factors differently at various points in time. As Albert Einstein said, "Not everything that can be counted counts, and not everything that counts can be counted." While we each do our best to ensure that all aspects of the product are considered, there are often times unforeseen market conditions and manufacturer changes which occur after publication that could render our rating obsolete. Please do not base any purchase solely on our conclusions, as they represent our product rating for the sample received which may differ from retail versions.

The performance of the Thecus N5550 is really outstanding, no question about it. It sits either at the top, or very close to it, within its target market. During timed transfers of 1GB and 10GB files the N5550 recorded Read speeds of 111 MB/s and Write speeds above 118 MB/s. These are the RAID 5 results, and the only ones that really matter, since I suspect 90%+ of all users will choose that operating mode. The Intel Atom D2550 processor inside was never maxed out during these tests, but the 2GB of SDRAM often was. It never seemed to have an impact on transfer speed though, as I was watching the performance in real-time for many of the test runs. The balancing act of capacity, speed and cost has to land somewhere, and Thecus put together a well-balanced package that definitely delivered the goods. The USB 3.0 performance is a much needed shot in the arm for interfacing with portable devices. The dual GbE network interfaces are perfectly suitable here, and the Intel chips support all the typical standards in use throughout the data center, if needed.

The five-bay form factor of the Thecus N5550 allows for the use of a display on the front of the unit, which was handy for system monitoring and for out-of-the-box setup. The status LEDs for each HDD are easy to see when the front door is open, and much less so when it's closed. The door hiding the drive trays has a number of stylish and functional features, and blends well with the remainder of the unit. It makes a big difference in the appearance, compared to models that have exposed drive bays. Thecus kept some of the controls on the inside, including the USB connector, plus the power and reset buttons. I'm OK with the power/Reset buttons but not with having to leave the door open just to access the USB jack that's behind it. It's the only USB 3.0 interface on the unit, so it's the one I want to use the most, too. The side and top panels are well finished, with a speckled powder-coat finish that doesn't show every fingerprint that comes near it.

The construction quality of the Thecus N5550 was just right, I thought. The drive trays are very nicely built, and slide in and out smoothly. The outer shell and the inner framework were modern, sturdy designs that fit together well and came apart easily when needed. I appreciate good mechanical design, especially when cost is a factor. When you take away everything that doesn't add value, you can sometimes come up with a very pleasing form. The design of the backplane with the steel backing plate bonded to the circuit board is an enhancement I haven't seen anywhere else. The front door was the only thing that felt a little fragile, as it flexes a bit when latching and unlatching. You tend not to notice the feet on networking components, but these got a little sloppy when the adhesive slipped and they moved sideways a bit. Thecus provides a 2 Year warranty, which is reasonable.

The Thecus N5550 is targeted to a growing class of NAS users, I think. The expansion of cloud-based services has really opened the public's eyes to the advantages of centralized storage, that's universally accessible. Thecus has all the basics covered in their add-on software modules, from cloud-based services to mobile access with both iOS and Android. Two additions to the N5550 bundle that stand out are the free McAfee Anti-Virus software that runs in the background on the NAS. This is not a subscription-based module, it's free for as long as you want. Secondly, Acronis True Image is included, which is a top-tier backup application. Once you get used to the feature set of a premium product like this, you'll be hooked for life - at least that's the idea. The local display module is a new addition that extends the capabilities of this NAS for both setup/configuration and media streaming. The fifth drive bay may seem like an odd addition, but users who want a RAID 10 configuration with a global hot spare won't think so. RAID 6 users are always looking for an extra drive bay as well, so don't be put off by the fact that four and six bays are much more common arrangements.

As of September 2012 the Thecus N5550 model was listed for $599.99 at Newegg. Given the number of drive bays you get, the Intel Atom CPU that's inside, the transfer speeds it achieves, the construction quality, and the features it offers, I think that's a very attractive price. For me, the NAS concept is still a good value proposition, and the Thecus N5550 offers very good value within that paradigm.

Benchmark Reviews has enjoyed testing a variety of network storage solutions, and with the wide range of products on offer from a number of vendors, anyone in need of a NAS server can find one to fit their current and future needs. The biggest problem is choosing one; that's why we go into so much detail in our reviews, to help you figure out what level of performance and features is right for you. If you need a staggering array of features and 10GbE-class performance, then you need to look elsewhere to meet those needs. If you just need the storage capacity, the high throughput and continuity of service that five bays of RAID 5, 6, or 10 provides, in a small tower package, then the Thecus N5550 is an excellent candidate for you.

Pros:

+ Very high transfer speeds
+ Local Display capability on VGA + HDMI
+ Excellent value
+ High quality construction
+ 2GB SDRAM is standard
+ USB 3.0 port on front panel
+ McAfee Anti-Virus S/W included
+ Acronis Backup S/W included
+ Quiet operation
+ Integrated 200W power supply
+ All the usual support apps available
+ Active Company and Community support

Cons:

- Can't migrate from single disk to RAID volume
- USB 3.0 port is hidden behind front door
- Must be on same sub-net as workstation, or use static IPs
- Adhesive on feet came loose
- Drive trays and bays not labeled 1,2,3,4,5

Ratings:

• Performance: 9.25
• Appearance: 9.00
• Construction: 9.25
• Functionality: 9.25
• Value: 9.25

Final Score: 9.20 out of 10.

Excellence Achievement: Benchmark Reviews Golden Tachometer Award.

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