The consensus view is that solid-state drives in storage arrays are not the ideal way of implementing solid state but will probably be the first step while other methods are developed.
Storage vendors have been claiming they would support SSD ever since EMC first revealed in January that it would put SSD in its high-end Symmetrix systems. EMC has since extended that support to midrange Clariion arrays. Hitachi Data Systems and Sun Microsystems also pledged support early, but they have yet to launch storage systems with SSD.
SSDs still cost around 10 times as much as disk, but a few announcements since last week indicated SSDs are getting closer to becoming another tier in storage systems.
- Compellent revealed plans to add solid-state drives to its Storage Center systems in the first quarter of 2009. Compellent executives claim their thin provisioning and data progression software will automatically reserve space for applications that can take advantage of SSDs so customers will need fewer SSDs for high-performance applications.
- Intel launched 2.5-inch X25-E Extreme SATA SSDs.
- Verari Systems said it would use Intel's new SSDs in its HyDrive disk blade and is exploring the use of Fusion-IO PCI Express flash boards in servers.
- Seagate awarded LSI a contract to supply the drive maker with a system on a chip (SoC) controller for SSDs.
Still, major vendors said solid state remains too expensive, and storage controllers built for sequential access rather than random access aren't the best method for running solid state.
"Disk controllers were not built for solid-state drives," said IBM distinguished engineer Clod Barrera. "SVC is a really fast array controller with copy services on top of it. It would be pricey, but the alternative is a much larger system with short-stroked drives. "We'll do the other thing (in array) too, because it's easy to do."
Hewlett-Packard distinguished technologist Jieming Zhu agrees putting solid state in disk arrays is the quickest way of getting it into enterprise storage. He said HP is planning solid state for its EVA midrange arrays, as well as using Fusion-IO cards in its servers. Using solid state in disk arrays "requires no OS and application changes now," Zhu said. Phase two will require OS and application changes.
"Eventually, the controller has to be taken into consideration<" Zhu said. "But that doesn't mean you can't take advantage of solid state now."
Zhu said HP's customers clearly want solid state, but they know obstacles remain. "Everybody wants it, but the majority takes a wait and see attitude. They look at us and say, 'How is HP going to address the performance issue? How is HP going to address the cost issue?' Cost is coming down, but reliability is an engineering matter," he said.
Other vendors, including Dell and Pillar Data Systems, say they will support SSD but are waiting for more customer interest. Dell executives have indicated they will have SSD in their storage systems – not just the Clariions Dell co-brands with EMC – but there is no great demand yet, said Praveen Asthana, Dell director of enterprise storage. "We have it in servers and notebooks now, and there is low adoption in those products," he said.
NetApp also has a dual-pronged plan for SSD. Chief marketing officer Jay Kidd said the ideal place for it is in the performance acceleration module caching devices NetApp rolled out in June. "We will support SSDs as traditional disk with volumes," Kidd said. "But we believe the best place to put SSD is in caching. We announced our performance acceleration modules, and it's not a big leap to see that as the place for SSD."
Sun has revealed plans to partner with Intel, Samsung and Marvel for SSD. But it is also working on a project it calls Lightning Flash, which Sun senior director of open storage Graham Lovell said combines flash technology with Sun's ZFS file system. "The best way to think of it is an IOPS accelerator. It increases the number of IOPS significantly," he said.
But even with products hitting the market, SSD is still more in the planning stage as far as customer adoption goes. "It's not going to overtake spinning disk technology any time soon, but it's something customers want to talk about," said Compellent CEO Phil Soran..