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Solidifying storage
Solid state drives have been playing a bit-part role in storage for some time now. 2008 really has been the year of the solid state drive thanks to lowering of prices and in great part to Intel, whose debut of the X-25 devices earlier in the year left many gasping for breath. Last week the biggest announcement of the year came when Hitachi said they were partnering with Intel to create enterprise storage devices based on Intel's units.

Forget the release of Intel's Core i7 processor or the iPhone 3G this will mark a fundamental change in how we store data. Hitachi is the first of the big players to twitch and move from only offering mechanical platter based storage devices and embrace flash memory. As is the case in most industries, where one goes the others follow, so similar announcements from the likes of Seagate and Western Digital shouldn't be too far behind.

Although Intel is a big player in the flash memory business, their primary business isn't making storage end-products (i.e. drives which slot into your machine). A retired Intel employee once told me that his former employer simply won't put a product into production unless it knows it can make a good 200-300% profit on it. Now, the storage business is a low margin one; just look at the consolidation that has taken place over the last decade. In the desktop space there are three (some may argue four) big players, Western Digital, Seagate and Hitachi with Samsung chomping away albeit slowly. Other manufacturers such as Fujitsu and Toshiba are merely there to make up the numbers. So using Hitachi as a vehicle for their extremely well received flash drives is a clever choice for both players. Hitachi, as is evident in articles such as this and others on the Web hit the headlines for producing drives based on technology which we already know offer blistering performance and Intel don't have to get their hands too dirty with the chores of distributing and providing warranty on solid state drives and instead concentrate on the profitable job of making the flash memory itself.

Hitachi will launch their solid state drives, SSDs, aiming for the enterprise market. Although this may sound rather odd, SSDs are suited perfectly for the high-end application of servers. Forget the rhetoric coming from Apple about SSDs being the perfect storage medium for notebooks, it's in servers were SSDs really shine. The most important metric in front line servers, the machines that serve up data to the client is I/O operations per second or IOPS. The biggest factor in IOPS performance is latency and because there is no platter that physically has to rotate until the head can read or write data to the platter in a SSD the latency is almost zero. Quite simply, for applications such as database servers SSDs are an absolute Godsend.

Drive mirroring

With SSD capacity reaching similar levels of SCSI and SAS drives both of which are in Hitachi's current product line there seems to be an obvious conflict between products. However Nick Kyriacou, Director, EMEA, Hitachi GST believes that SSDs "will complement existing enterprise class drives and are intended for storage applications that require extremely high I/O performance and power efficiency. SSDs create a new tier in the storage hierarchy, expanding the overall storage market."

Judging from Kyriacou's answer it seems that Hitachi are positioning their SSDs as an ultra high performance drive while leaving their SCSI and SAS units to perform the job currently served by higher end SATA drives - provide high capacity. Kyriacou hints as much by saying that "enterprise-class HDDs continue to provide a solid value proposition for the majority of enterprise storage users." Those companies who have invested heavily in SANs which utilise these units are unlikely to throw them away in the short term, however the significantly lower running costs of SSDs may tempt more than the usual early adopters in this current economic climate. Kyriacou believes that enterprise customers will see Hitachi as a one-stop vendor for enterprise drives, whether they be SCSI, SAS or SSD based.

Here to serve you

It seems that SSDs are set to grow up in the harsh conditions found in the server room rather than below any desk. Kyriacou says there are no plans for desktop orientated SSDs by Hitachi at this point. This leaves the door open for the other big hard drive player who has banked heavily on SSDs, Samsung, to make inroads into the high volume market. The Korean manufacturer already provides Apple with the SSDs found in Macbook Pros and it will be interesting to see if Hitachi are displaced as the primary hard drive supplier in the workstation orientated Mac Pro.

We asked Kyriacou whether a hybrid platter based hard drive along with a large SSD like cache in the region of several gigabytes was in Hitachi's pipeline. He refused to rule it out completely saying that "SSDs combined together with traditional enterprise drives in a storage hierarchy model should deliver the performance/cost requirements of the vast majority of customers." It does seem surprising that such a unit has yet to surface, but it may provide the ideal entry point for more cost effective devices aimed at the workstation market.

A fundamental problem with flash memory that is found in SSDs (along with other media such as SecureDigital and CompactFlash cards) is the number of write cycles they have before becoming useless. Whereas in portable flash memory it is rare to hit the write cycle limit when used as a system hard drive, flash write cycles can be reached in a matter of months given a particular usage pattern. In order to combat this Kyriacou says Hitachi have implemented a number of technologies in order for them to offer the same length of warranty that is found on their enterprise level drives at present.

Asked to provide some details about these techniques, Kyriacou obliged saying that their units will contain "a fail-safe write cache helps to improve overall performance, and also to reduce write cycles to the flash. Wear-levelling algorithms also distribute hot spot accesses to prevent excessive write cycles. The hardware and firmware have extensive correction capabilities, and can check and correct data as it is moved within the SSD. In addition, there is reserve capacity allocated to help with wear-levelling management, or any other reallocation activity the drive requires."

Few doubt whether SSD hard drives will eventually overthrow the current crop of platter based units but what Hitachi have done by announcing their partnership with Intel is sped up that process greatly. Although drives are still a few months off from appearing in servers it's a foregone conclusion that it won't be long before Hitachi or another big hard drive manufacturer decides to aim at the desktop market with SSDs. Hitachi may not have caused the revolution but they have certainly sped it up.


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