Hard drives

Solid State Disk Will Go Mainstream in 3, 2, 1...

Meanwhile, Back in the Data Center

Flash memory-based SSDs are also making their way into the enterprise data center, where the performance and power savings of SSD are attractive. The main issues SSD needs to overcome in the data center are reliability, price and user acceptance. "It's still an untested market," Chander says. "IT managers have a lot of mission-critical data that they're not ready to store in SSD."

In EMC Corp.'s case, SSD is positioned as a high-performance "tier zero" in the company's Symmetrix DMX-4 array. "EMC is saying you can put frequently accessed pieces of your data set on SSD, to increase system performance," Janukowicz says. Less accessed data can remain on Fibre Channel drives.

EMC is using SLC NAND chips from STEC Inc., but it says it's also adding a lot of its own intellectual property to ensure reliability that's on par with Fibre Channel, as well as the ability of the array to take advantage of SSD speeds and I/O capability. The company expects SSD pricing to be on par with the very highest end Fibre Channel drives by the end of 2010.

Meanwhile, Sun Microsystems Inc. has unveiled a plan to offer 2.5-in. and 3.5-in. SSDs across its servers and storage products in the second half of this year. It also tweaked its ZFS operating system to handle SSD. In Sun's case, the role of flash memory is as a high-speed cache, Stokes says. Sun claims that it can dramatically boost performance while lowering power consumption by coupling an SSD-based disk cache with a pool of slower, cooler-running drives, he says.

The company believes there will be rapid adoption of SSDs for performance-intensive workloads in the next six to nine months, which Stokes sees as a compressed timetable but similar to the track Intel says it's on. Janukowicz agrees with this time frame. "We're seeing uptake even today," he says, "and we suspect that will continue into 2009 and 2010 as systems get more broadly accepted."

But according to Chander, the world isn't quite ready for SSD at the enterprise level. "I think it's aggressive," he says. "Vendors can offer all that, but they need to take into account the box vendors and IT managers who are buying it and whether they're comfortable displacing hard disk with SSD."

Give it two and a half years, he says. SSD vendors say their drives have a guaranteed life of five years, and once people cross the half-life of that and the system hasn't failed, "word of mouth will help rally the market, and SSDs will take off," he says.

Where SSD really shines is in read performance, Janukowicz says, although vendors are currently working to increase write speeds. "A lot of the development work is to improve write performance, as well as read performance, he says. According to Kerekes, the asymmetry of read-to-write IOPs will improve to 5-to-1 by 2010, but won't progress beyond 4-to-1.

Energy savings may also help close the price gap, especially in data centers where companies have overallocated storage to get a certain I/O performance. "You can replace 10 hard drives with one SSD and the same I/O performance," Janukowicz says. EMC says a 1TB array of solid-state drives would draw 38% less power compared to hard drives.

Also accelerating SSD in the enterprise is the drop in NAND prices, according to Stokes. "The combination of dropping NAND prices and increased capital expenditures on NAND production (up by 20%, according to iSuppli) will accelerate enterprise adoption of SSDs," he writes on the Ars Technica site. "Rising data center power budgets and networked storage latencies have already made the case for SSDs in the data center, but the SSD price drop and the ONFI 2.0 spec will serve to seal the deal this year."

In any case, according to Robin Harris, an analyst at the Data Mobility Group who also runs the StorageMojo blog, SSD at the enterprise level doesn't need absolute price parity to win against high-end Fibre Channel drives. "Getting within 30% should do it for most people," he says on his blog. "Their performance advantages are worth at least that."

Kerekes agrees that SSD should be seen as a disruptive technology; in other words, rather than looking at price per byte, users will eventually consider the technology's other value propositions. It's similar, he says, to comparing a bike to a car or the PC to a typewriter.

"SSDs are seeping into many market applications long before the time that would be predicted by analysts who cling to the outmoded model of cost per byte parity with hard disks," he says on the StorageSearch site. "The SSD market in the long term will be bigger in revenue than the HDD market is today."

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