|EonNAS 850X NAS Network Storage Server|
|Reviews - Featured Reviews: Network|
|Written by Bruce Normann|
|Thursday, 14 February 2013|
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Technology Details: EonNAS Pro 850X NAS Server
The EonNAS Pro 850X uses one of the Intel Sandy Bridge Core i3 Dual-Core CPUs, based on 32nm fabrication technology, the i3-2120. Introduced in Q1 of 2011, the i3-2120 runs at a speedy clock frequency of 3.30 GHz. Some models may use the i3-2125 version, which is equivalent as far as the CPU internals, but the 2125 features HD-3000 graphics instead of HD-2000. It's also scheduled for discontinuance in 3Q2013, while the 2120 has no published EOL at this time. The integrated graphics controller runs at a relatively fast clock speed of 850 MHz, which also isn't really important for this NAS, since it doesn't normally output video. Lastly, the 3MB Intel Smart Cache and the integrated memory controller that supports DDR3-1066/1333 DRAM are both performance enhancing features, and a big upgrade from the 1MB cache and DDR3-800 capabilities of the Atom CPUs frequently found in smaller NAS units. The CPU package fits in the normal LGA1155 socket, and the TDP is a modest 65W. The CPU does not support the AES NI extensions for encryption, so don't expect to be able to encrypt your disks without a major performance penalty. In the foreground of the image below is the single x16 PCI Express 2.0 expansion slot, which is used to provide a high bandwidth connection between the drive controller and the CPU. (The drive controller that normally resides there was removed for this image.) Note, this PCIe connection goes directly to the Core i3 CPU; it does not go through the Platform Controller Hub.
The motherboard is a pretty standard small-form-factor design, and in an eight-bay NAS like this, standard designs don't cut it, if used alone. Infortrend uses the single PCI 2.0 slot to radically expand the capabilities of the basic Intel architecture in order to handle the demands of managing eight disks in high-order RAID, plus the two 10GbE network interfaces. The custom PCB below has two internal SFF-8087 Mini-SAS connectors that are cabled up to the eight-position SATA backplane (see the two red braided cables, above). These connectors are most often seen on RAID controllers, with fan-out cables attached. Here, the copper traces on the backplane do the fanning out to the eight SATA II ports; the cables are SFF-8087 on both ends. The four small ICs surrounding the SFF-8087 ports are JMB362, 1-lane PCI Express to 2-port Serial ATA II Host Controllers from JMicron. They interface directly with the eight SATA drives connected to the backplane. The heatsink on the left is covering up a PCI Express switching IC that takes the eight PCIe lanes wired up to the card edge and parcels them out where and when they're needed. Just above the card edge is a small connector which takes some of those PCIe lanes off to a small daughterboard that provides the two 10GbE network interfaces. As I said above, this expansion card is a very custom design, which allows Infortrend to use a common spec Intel Core-i3 motherboard in a very specialized application that would normally choke a standard design.
Instead of using the Intel Platform Hub Controller to provide the SATA interfaces, the EonNAS 850X uses eight lanes of the x16 PCI Express interface that comes right out of the CPU. In a typical desktop system you might use that for a video card, but Intel doesn't restrict the use of the interface; the data sheet calls out Graphics or I/O as potential uses for the data stream. In this case, its disk I/O that's coming across the wire and its eight independent data streams. What do you do when you have multiple data feeds that you need to consolidate - you put in a switch, right? Most people only think of Ethernet when switches are mentioned in the same breath as computers, but all kinds of data needs switching, not just network traffic. The biggest chip on the expansion board, and the one doing the most work, is the IDT 89H24. According to its maker, the "89H24NT6AG2 is a 24-lane, 6-port system interconnect switch optimized for PCI Express Gen2 packet switching in high-performance applications, supporting multiple simultaneous peer-to-peer traffic flows." Sounds like a smart way to manage the data from eight disks running in higher order RAID, if you ask me. In a clear division of labor, the high-level RAID functions are handled by the CPU, while the frenetic transfer of data from multiple sources is handled by a switch. I keep coming back to the fact that at some point, once you have more than 4 or 5 drives in a complex array, you can't use the standard PC-based architecture anymore. Smaller NAS models do well to take advantage of the "free" SATA interfaces that come along with the standard Intel package of CPU and Southbridge, or PCH; the big dogs need to think outside that box.
The four drive controllers are sourced from JMicron, and they each support dual connections of the SATA 3Gb/s specification, also known as SATA II, for interfacing with the drives. The other side of the function block is PCI Express, Base Spec. Revision 1.0a. Since each lane of PCI Express is capable of transferring 2.5Gbps, there's plenty of bandwidth supporting each chip to service two HDDs. If SSDs were installed in the drive bays, they would each be capable of saturating this interface, as they can each move a maximum of 3.0 Gbps of data through each of the SATA II connection, but only when new. Even Enterprise-class SSDs can't meet those kinds of specs as NAND wear takes its inevitable toll. Most NAS devices are still optimized for HDDs, not SSDs. Even at the Enterprise level, where Storage Area Networks (SAN) are a common choice for storage, the current trend is for hybrid devices, with a mix of HDD and SSD.
The EonNAS uses a 1GB Disk-on-Module (DOM) as the boot device. It's built and configured with a USB interface rather than IDE or SATA, courtesy of the Silicon Motion SM325QF flash memory controller. As an outboard device, it's easier to interface it this way; if the DOM was integrated on the motherboard, I would expect to see the more traditional disk interface being used. Serving up a Sun Solaris operating system is the dog's life for a flash memory chip (SSD Boot Drive, anyone...?); this module never breaks a sweat.
The two Gigabit Ethernet controllers are supplied by Intel and they use a tag-team approach to provide both Media Access Control (MAC) and the Physical Layer (PHY) for the RJ-45 ports. The WGG82574L and the WG82579LM combine forces to provide the MAC and PHY functions. The latter chip was just launched in 1Q2011, so Intel is keeping things current in this area. Each chip connects to the rest of the system by an x1 PCIe Rev. 1.1 interface, and 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, even though they're not very well known for it by the general public, so it's not a big surprise that NAS vendors choose their products for implementing integrated GbE interfaces. The EonNAS 850X also has two 10GbE interfaces, which are just what's needed to support a large, high performance NAS like this. I'll cover them, and their performance enhancing capabilities, in a follow-up article.
Last, but not least is the 8 GB of DDR3 memory that is standard on the EonNAS Pro 850X. It's carried on two 4GB DIMMs, and the modules supplied by Apacer are rated for DDR3-1333 with timings of 9-9-9 for CL-tRCD-tRP. The SDRAM chips themselves are sourced from Elpida. This is the maximum memory speed supported by the Intel Core i3 CPU, so no expense was spared with the supplied DRAM. Given the impact on overall performance that RAM has for the Solaris-based O/S and the ZFS file system that comes along with it, I'd say Infortrend was wise to max out this particular subsystem.
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. Once the system completes its boot process, and gets into normal operating mode, it settled in at about 54 watts of power consumption with one drive installed. With all four drives installed, it idled at 75W. During Write operations, it drew 95W, and Read operations drew 85W. When the ½ hour default sleep timer kicked in and the drives were powered down, the power consumption went down to 51W. When the unit is turned off, it still consumes 2W in Vampire mode; be aware that even when it's turned off, the integral 430W 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 EonNAS Pro 850X. The next couple of sections are somewhat shorter than we're used to seeing with consumer-grade NAS systems, and 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.