Monday, March 24, 2008

Snap Server vs the Competition: NAS Storage Comparison

Bake-Off: Network-Attached Storage

Whenever the conversation turns to storage, SANs tend to hog the spotlight. However, there are valid technical and financial reasons for picking NAS, especially when several machines need access to the same set of data.

CRN Test Center reviewers set out to examine middle-of-the-road NAS products that support 2 Tbytes to 4 Tbytes of storage space and have a Gigabit Ethernet interface. The five products that made the cut were Adaptec Inc.'s Snap Server 520, Buffalo Technology Inc.'s TeraStation Pro II, Hewlett-Packard Co.'s ProLiant DL320s Storage Server, LaCie's Ethernet Disk, and Netgear Inc.'s ReadyNAS NV+. These capacities represent the maximum for each unit, which were not the same as the as-tested capacity.


Reviewers calculated technical rankings by looking at performance, feature set and capacity-per-dollar. Capacity-per-dollar was calculated on a standard 2-Tbyte storage system. Channel programs were also considered.

In the interest of standardizing storage types, each system was configured with a single RAID 5 array setup at the largest size possible. Each unit was connected to the same switch as the testing PC.

Two tests measured performance. First, two directories with various file types were copied from the testing PC to the NAS and back again. The 1.2-Gbyte directory contained 23 files and the 3.2-Gbyte directory had 41. Operations were timed.
Then Iozone testing software measured I/O performance on files from 32 Mbytes to 10 Gbytes. Results were plotted to see which system had the best overall performance across various file sizes.

Other considerations included environmental factors such as noise level, power draw and heat output; feature set; applications; types of connectivity; supported platforms; failover capabilities and management options.

Running the Numbers

Iozone tests both file sizes and record sizes when measuring read/write speeds. When the results were plotted, HP ProLiant DL320s Storage Server creamed the competition. It measured 815,151 KBps (796 MBps) on writing a 32-Mbyte file with 64-Kbyte records, while the next highest performer, LaCie Ethernet Disk, measured 285,787 KBps (279 MBps). Oddly enough, LaCie Ethernet Disk has less features but consistently outperformed Adaptec Snap Server 520 across all file sizes, while Buffalo's TeraStation Pro II and Netgear's ReadyNAS NV+ had virtually identical results. Buffalo and Netgear win points for consistency—their speed remained essentially the same regardless of file size. After 128 Mbytes,
however, LaCie's read/write speeds dropped close to Adaptec's speeds, which remained slightly better than Buffalo and Netgear. The HP results remained consistently high, but had a sharp decline after 1 Gbyte, bringing it closer to the rest of the competition in order of magnitude.

HP ProLiant DL320s Storage Server

HP's ProLiant DL320s Storage Server snatched first place on the combined strength of its channel program, I/O performance and features. Priced at $6,666, it was the second most expensive offering in this comparison, but it's worth it for environments where performance matters.

The ProLiant DL320s test system was a 2U enclosure with 12 250-Gbyte SATA drives, providing up to 3 Tbytes of storage. SAS drives are also supported. The ProLiant DL320s Storage Server comes in several size configurations, including 1.7 Tbytes, 3 Tbytes, 3.6 Tbytes, 6 Tbytes and 9 Tbytes. It can easily support 25 to 200 users.

Since the DL320s does not come in units lower than 3 Tbytes for SATA disks, the price-per-capacity is presented at 3 Tbytes for this system only.

The ProLiant DL320s Storage Server ships with the Microsoft Windows Storage Server 2003 RC2 operating system preinstalled and preconfigured. When powering it on, the system runs the Rapid Startup Wizard, which collects
network configuration information. Once the wizard is complete, the system is available over CIFS, Samba, NHS, HTTP, FTP, WebDAV, AppleTalk and NetWare file protocols. Reviewers used the Storage Manager interface to create a new 2-Tbyte RAID 5 volume spanning all 12 drives.

For all practical purposes, this is a regular Windows server—but one that has been optimized to be a storage device. The registry has been tweaked to deliver files faster and data duplication features have been added. It comes with a dual-core Intel Xeon 3070 2.67GHz processor, 2 Gbytes of memory (expandable up to 4 Gbytes), a DVD drive and dual hot-plug power supplies. VARs can install security applications and third-party storage applications to complement HP's Storage Manager tool. It can also function as a print server.

To simulate drive failure, reviewers pulled the drive out of the chassis at random. The system logged the problem and immediately rebuilt the array so data was not lost.

HP performed better on large, multifile directories. It took 2:19 minutes to read and 2:11 minutes to write 1.2 Gbytes of data and 7:59 minutes to read and 6:11 minutes to write about 3 Gbytes. It was consistently faster on the writes than on the reads.

Netgear ReadyNAS NAV+

Netgear ReadyNAS NAV+ nabbed second place on the strength of its channel program and its deep feature set. The ReadyNAS matched more expensive competitors feature for feature at a significant cost-savings.

It is a desktop solution that packs a large wallop into a small case. The price-per-capacity, $1,599 for 2 Tbytes, is solidly in the midpoint compared with the other four products.

The ReadyNAS NV+ supports RAID 0, 1 and 5 as well as its own X-RAID (Expandable) configuration. The device has four hot-swappable drive slots and an integrated backup manager that allows for one-button backup to an external USB hard drive or remote server. It is expandable via three USB 2.0 ports. The ReadyNAS NV+ can support up to 20 concurrent users and can also be configured as a DHCP server and a print server. It has an informational LCD panel concealed
behind a mirror on the front that is only visible when lit.

The unit comes preconfigured in X-RAID to expand storage capacity when drives are changed. Reviewers manually reset the system to create the RAID 5 volume. Although the administrator console is browser-based, the RAID configuration is done through a client application called RAIDar. This application is easy to use, but it's an extra program that solution providers need to remember. Drive failure was simulated by pulling out a drive. When the drive was replaced, the system needed to rebuild the array, which took a little more than four hours.

The intuitive administrator console allows all kinds of ReadyNAS management, going so far as to allow recalibrating the fan and show temperature readings down to each disk.

On performance, the ReadyNAS took 53 seconds to read and 1:11 minutes to write 1.2 Gbytes of data and 16:48 minutes to read and 10:25 minutes to 3.2 Gbytes of data. At 69 dB, noise levels were comparable to the other units
tested, but seemed much louder as it was a desktop unit. It drew only 58 watts of power.

ReadyNAS is built with the future in mind. As higher-storage capacity disk drives hit the market, it will be able to accommodate them, all the way to the theoretical four 16-Tbyte hard drives that will max out the system's storage capacity at 64 Tbytes

Adaptec Snap Server 520

Adaptec Snap Server 520
, despite its robust feature set, lost out to Netgear and ended up in third place. At a list price of
$6,445 for a 2-Tbyte configuration, the Snap Server has the highest price-per-capcity value compared with its competitors. Netgear had the advantage of having a lower price-per-capacity while matching many of Snap Server's features. However, the Snap Server 520 stands apart from its competition in one regard: While the other vendors submitted storage products, Adaptec submitted a complete solution.

With two Gigabit Ethernet ports, a print server, backup and antivirus software, the 1U enclosure comes with four 750-Gbyte hot-swappable SATA drives. Its two-line LCD displays status information, system ID and IP address. The Snap Server is a system with an eye toward future growth. The box can have its internal memory upgraded up to 4 Gbytes. Seven expansion bays make a maximum capacity of 66 Tbytes possible.

Mounting the rack on rails proved to be a frustrating exercise. Otherwise, installation was simple. The extremely well-laid out, browser-based administration interface allowed reviewers to see the status of, and configure, almost everything imaginable. It is clearly one of the unit's high points.

Connecting to the shares was as easy as typing the path within a command line or, preferably, mapping a drive letter to it from a remote machine.

At nearly twice the size of the LaCie, the extra surface area allowed the Snap Server to operate at almost room temperature, 69 degrees, in the front of the case, and only 10 degrees warmer in the back. This was much cooler than the other contenders. On the flip side, at 78 dB, it was a noisy system and drew about the same amount of power as the HP ProLiant DL320s, peaking at 130 watts during startup before dropping down to the 90s.

Read and write tests showed that the Snap Server's speed improves somewhat with larger files. It took the longest to read and write 1.2 Gbytes of data at 2:11 minutes to read and 2:09 minutes to write. It took 8:37 minutes to read and
15:26 minutes to write 3.2 Gbytes.

LaCie Ethernet Disk

Even though it lacks many of its competitors' features, the LaCie Ethernet Disk was a favorite during testing. The lack of features such as individual disk status information, support for the NFS protocol and a front LCD panel hurt the Ethernet Disk in this particular comparison and helped land it in fourth place, but its performance and price-per-capacity stand out.

Despite being the cheapest unit on price-per-capacity, at $949 for 2 Tbytes, the LaCie Ethernet Disk turned in better performance than two of its competitors, Netgear and Buffalo. LaCie Ethernet Disk has four hard disk drive slots and can
support as many as 25 users simultaneously. The test system had 4 Tbytes of storage and is priced at $1,999.

LaCie ships with a Microsoft Windows XP Embedded operating system preinstalled. The OS allows Ethernet Disk to easily join a Windows domain using Active Directory. It also supports Samba, AFP, FTP, HTTP and Bonjour file-sharing protocols. There are four high-speed USB 2.0 ports for backup onto external hard drives, or for capacity expansion. There are also PS2 mouse/keyboard ports and a VGA monitor connector, none of which LaCie recommends using.

The 1U rack-mountable unit came with little rubber feet (or as one reviewer called them, "booties") to cover the protruding ends, allowing it to be safely used as a stand-alone device. Optional rails for rack mounting are also available. Installation and configuration was, by far, the easiest of all the units tested. Reviewers mounted the system in a rack, connected the power and network cables and turned it on. After boot, there is already a share called Public created and ready to use. The browser-based, tabbed administration application is intuitive, but sparse on features.

Although generating more heat than the others, the LaCie was quiet and drew considerably less power than the other products. The power draw peaked at 66 watts during startup and stabilized at 63 watts.

While Ethernet Disk lacks features, it performs well. It took 1:11 minutes to read and 1:30 minutes to write 1.2 Gbytes of data, and 13:02 minutes to read and 6:41 minutes to write 3.2 Gbytes of data.

Buffalo TeraStation Pro II

Despite having the second lowest price-per-capacity, at $1,200 for 2 Tbytes, the TeraStation Pro II from Buffalo placed fifth because it lacked the robust feature set and performance capabilities of its competitors.

Rackmount and desktop versions are available in 1-Tbyte, 2-Tbyte and 4-Tbyte capacities. A desktop is also available in 3 Tbytes. The TeraStation test system was installed with four 1-Tbyte 7,200-rpm hard drives to get a 4-Tbyte storage capacity. The 4-Tbyte TeraStation Pro II is available for $2,200.

Drives can be configured in RAID 0, 1, 5, 10 and JBOD. External drives or additional units can be linked via its two USB 2.0 ports. A LCD display shows the drive and the system's status, network configuration and any error messages. Once the TeraStation Pro II is hooked up on the network, it immediately obtains an IP address from the DHCP server and displays it on the LCD screen. Once it has an IP address, the TeraNavigator software, available under Windows and Apple's OS X, detects it. The NAS Navigator is the client utility and displays system information and configuration settings. The TeraStation Pro II supports Samba and FTP for file sharing and can be synced with a time server. The system can support Active Directory integration and DFS. The fault-tolerant RAID mode allows hot-swapping SATA drives. It also has a built-in FTP server.

The system is quiet, despite a large fan, even more so as a desktop unit and is quieter as a desktop unit than as a rackmount. The heat-release design keeps the unit very cool, even after eight hours of intensive file copy operations. It drew more power than the sleeker LaCie system or the comparable Netgear box, drawing a peak of 94 watts during startup, stabilizing at 86 watts after several hours.

The TeraStation Pro II was the slowest performer, taking 25 minutes to read and 31 minutes to write 2 Gbytes of data. Other data sizes were not tested as a result

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