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A look at four X25-E Extreme SSDs in RAID


Obscene opulence at its finest
— 10:17 PM on January 26, 2009

Intel's X25-E Extreme SSD is far and away the fastest flash drive we've ever tested. Sure, it only packs 32GB of storage, and yes, you'll pay a princely sum for the privilege. But with a smart storage controller, near-instantaneous seek times, and the ability to sustain reads at 250MB/s and writes at 170MB/s, the X25-E actually represents good value if you quantify its performance per dollar. That might not be how most folks look at value in the storage world, but for the demanding enterprise environments at which the Extreme is targeted, it's often the most important metric.

While the X25-E's dominating single-drive performance would surely satiate most folks, its target market is likely to seek out even greater throughput and higher transaction rates by combining multiple drives in RAID. The performance potential of a RAID 0 array made up of multiple Extremes is bountiful to say the least, and with the drive's frugal power consumption and subsequently low heat output, such a configuration should cope well in densely populated rack-mount enclosures. Naturally, we had to test this potential ourselves.

Armed with a high-end RAID card and four X25-Es, we've set out to see just how fast a RAID 0 array can be. This is easily the most exotic storage configuration we've ever tested, but can it live up to our unavoidably lofty expectations? Let's find out.


Ramping up the RAID
The software RAID solutions built into modern south bridge chips are more than adequate for most applications—my personal desktop and closet file server included—but they're probably not the best foundations for a four-way X25-E array. Such an impressive stack of drives calls for a RAID controller with a little more swagger, so we put in a call to Adaptec, which hooked us up with one of its RAID 5405 cards.


The 5405 features a dual-core hardware RAID chip running at 1.2GHz with 256MB of DDR2 cache memory. We'll be focusing our attention on RAID 0 today, but the card supports a whole host of other array configurations, including RAID 1, 1E, 5, 5EE, 6, 10, 50, 60, and 36DD. Ok, so maybe not the last one.

Dubbed a "Unified Serial RAID controller," the 5405 works with not only Serial ATA drives, but also Serial-Attached-SCSI hardware. The card itself doesn't have any, er, Serial ports onboard. Instead, it has a single x4 mini-SAS connector (at the top in the picture above) and comes with an expander cable that splits into four standard Serial ATA data cables. If you want to use the 5404 with Serial-Attached-SCSI drives, you'll need to add a SAS expander cable or have a compatible backplane or direct connect SAS storage.

To ensure compatibility with cramped rack-mount enclosures, the 5405 is a low-profile card with standard and short mounting brackets included in the box. It also has a PCI Express x8 interface, making it compatible with a wide range of workstation and server motherboards, in addition to standard desktop fare. PCIe x8 slots tend to be rare on desktop boards, but fear not. We were able to get the 5405 running in our test system's primary PCIe x16 graphics card slot without a fuss. Since it only has eight lanes of electrical connectivity, the 5405 can't make the most of an x16 slot's available bandwidth. However, for four ports, an aggregate 2GB/s of bi-directional bandwidth should be more than adequate—even for X25-Es.

As one might expect, the 5405 isn't cheap; it costs $335 and up online. Adaptec does provide three years of warranty coverage, though. Drivers are also available not only for Windows, but also for OpenServer, UnixWare, Solaris, FreeBSD, VMware, and both Red Hat and SUSE Linux.