Repost from Storage Channel Pipeline: SSD Arrays

August 26, 2010

Posted by: Eric Slack
SSD, Eric Slack, Storage Channel

The term “SSD” has usually been a mnemonic for “solid-state disk” drives, as in flash memory modules that are put into traditional disk drive form-factor packages. This format is perhaps the easiest to integrate into an existing storage environment, either as replacement server-based disk drive(s) or for use in an external disk array. But this packaging includes a SAS or SATA interface for each SSD itself and for legacy external arrays and involves running solid-state storage devices through a controller designed to support spinning disk. New, dedicated SSD arrays are available that integrate the flash memory modules directly onto cards inside the array and skip the disk form-factor package altogether. Storage Switzerland was briefed by two of these companies at the recent Flash Memory Summit.

Violin Memory’s Memory Array supports up to 10 TB of single-level cell (SLC) flash on hot-swappable, internal circuit cards the company calls “VIMMs” in a 3U enclosure. Card-mounted flash provides better density than drive form-factor SSDs, lowering the cost per gigabyte and providing better performance through the elimination of the SAS or SATA protocol. Putting more flash modules together on each card also improves the write performance, since writes can be spread over more flash modules and overhead can be done more efficiently.

Nimbus Data Systems’ dedicated flash array also puts flash modules onto hot-swappable circuit cards, or “flash blades.” A 2U array holds 24 of these blades and provides 2.5 TB of capacity. Nimbus’ HALO operating system includes storage features like snapshots and replication but also deduplication and thin provisioning. These capabilities give the system a much larger effective capacity and lower its cost per gigabyte.

Solid-state storage is moving into the dedicated array space with some compelling capabilities and price/performance numbers. These “pure flash” SSD arrays deserve a closer look by any VAR that’s serious about storage.

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Storage Switzerland Repost: Flash Memory Summit Briefing

August 26, 2010

George Crump, Senior Analyst

I sat down with Nimbus Data Systems’ CEO Thomas Isakovich at the Flash Memory Summit to get an update on their Sustainable Storage system. With their product the S-Class flash storage system, Nimbus Data is delivering potentially the first storage system that is completely solid state and has a full compliment of data services. These are capabilities that customers in the enterprise market have become accustomed to like thin provisioning, snapshots, replication etc… To those features they add the ability to do inline deduplication and compression to get a 10:1 storage efficiency rate which brings a flash only system closer to cost parity with a mechanical drive based storage system.

It has always seemed to me that solid state becomes a perfect platform for deduplication and compression. While there may be some performance impact to implementing the capabilities, SSD for many environments has storage I/O capability to spare. To the user and the application, the impact of implementing deduplication and compression are often unnoticeable. The payoff is that you are gaining extra storage space on a tier of storage where capacity comes at a premium still today. A 10X gain on storage that is already inexpensive like SATA is interesting, a 10X gain on storage like Solid State is very compelling.

As you would expect in a solid state only storage system performance is very good. The system has the ability to generate over 1 million IOPS per second but does so at a cost point that is within the reach of a very broad set of use cases. This could be an ideal platform for both desktop and server virtualization projects as well as high transaction database applications and even extends into the HPC market.

This performance also helps in maintaining system integrity. The Nimbus S-Class has RAID protection to protect from flash module failure similar to how a legacy storage system would use RAID to protect from a hard drive failure. The difference is the speed at which the S-Class can rebuild from a failure and the performance impact during that rebuild as compared to traditional storage systems. With traditional storage systems you  have to wait hours and in some cases days for the rebuild to complete all the while trying to balance rebuild performance vs. user performance. With the S-Class rebuilds take about 30 minutes with little to no impact to overall performance and minimal exposure time.

Where Nimbus is clearly focused though in on the overall power savings aspect of their Sustainable Storage System; the amount of power required to deliver an IOP. In high performance storage systems that need hundreds of disk drives to meet performance demands the cost to power and cool those systems can be staggering. The S-Class delivers up to 6,000 IOPs per watt and 675,000 IOPs per floor tile.

Storage Switzerland’s Take

This is the first storage system we have seen with a complete compliment of data services. Its use of deduplication and compression to bring solid state closer to price parity to mechanical drives makes for a compelling tier 1 storage solution for data centers that are struggling with I/O bound workloads.

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