VelociRaptors In RAID 5, A Case Study In Speed

If you were the type to think of 2.5" drive technology only in terms of notebook products, then recently, Western Digital probably helped expand your horizons a bit.  With the release of their VelociRaptor 300GB SATA hard drive, mainstream users were exposed to the advantages of the high transfer rates associated with 2.5" platters rotating at 10K RPM, with four access heads pulling data.  Though packed in a 3.5" form-factor for desktop system compatibility, the 2.5", dual 150GB platter platform that the VelociRaptor was built on allows it to outperform virtually all standard 3.5" SATA drives on the market today, even WD's 10K RPM Raptor WD1500 series. 

However, the VelociRaptor is definitely targeted to the performance enthusiast, with a price tag currently at $1/GB (MSRP $299).  Regardless,
when you consider the upside potential performance gains and the fact that a hard drive is easily the slowest component and limiting factor in many areas of overall system responsiveness, it's obvious this new Raptor will do well from a retail perspective.  But what about the Data Center?  Actually, when you consider the average 146GB 10K RPM SAS drive retails for about the same price as the new VelociRaptor but with half the capacity, just maybe a few folks in IT will poke their heads up out of their cubicles long enough to give the VelociRaptor a look as well.  Of course, that all depends on the usage model, as clearly there are other advantages to SAS in terms of error reporting and recovery, but if the metrics are all about reliable, cost-efficient performance, there may be a solid case for the VelociRaptor in that storage server as well.  Article Update, 6/28:  We should throw in one rather significant caveat here however.  Currently these new drives do not have an industry standard connector layout.  They won't fit in a 2.5" sled for a standard hot-swap chassis config but we've been told WD is planning on coming out with a new model that will offer a standard (3.5" presumably) connector layout.

Regardless, it was with a few of these questions in mind that we decided to RAID up not two but three WD VelociRaptor drives in a RAID 5 configuration with an
Areca PCIe X8 hardware RAID card, to see what the numbers looked like.  This is only a quick-take on read performance but it certainly gives you a sense of scale and what these drives are capable of in the right environment.

WD VelociRaptor 300GB X 3 - RAID5 Areca PCIe Hardware SATA RAID
Windows Vista SP1 - NTFS

WD VelociRaptor 300GB X 3 - RAID5 Areca PCIe Hardware SATA RAID
Windows Vista SP1 - NTFS

A quick gander at the graph above shows relatively linear performance across the entire 600GB volume with some small vallies along the way.  The burst speed recorded was robust 598MB/sec, according to HD Tach, which is about on par with what we've seen from WD's Raptor WD1500 line in this configuration.  However, average read performance is through the roof, with a 209.4MB/sec land speed record set for what we've seen in our labs and about a 33% performance gain over what we've seen with Raptor WD1500 drives in RAID 5 on the Areca controller.  Finally, random access clocks in at a snappy 7.2ms. 

So in short, whether you an end user with just a need for speed, or an enterprise user looking for mission critical performance, the VelociRaptor definitely has strong merits.  Straddling the cost line between standard, bulk SATA drives and high-end 10K RPM SAS, WD's new beast offers an interesting and compelling paradigm.

The Data Center, HotHardware's new community for IT professionals, is sponsored by Dell's Future of Storage. This article is part of our ongoing series of topics and discussions related to IT, Enterprise Storage and related storage technologies.

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