Just when the rest of us were finally getting our heads around the notion of three-tiered storage - fast disk, fat disk and tape - along comes a fourth one. Acopia Networks this week said it's the first to deliver Tier 0 - superfast storage used as application working space.
Acopia said that while anyone could implement a Tier 0 using solid-state disk, its version has the advantage of also having a single file system for all storage types. That means all the storage is seen as a single volume, making it easier to move files from one tier to another.
"You take massive amounts of memory in a server and address it as a disk," said Acopia technical architect Martin Cooper. "The uniqueness is that with our in-line file virtualisation we present a consistent name-space, so it doesn't have to be a separate volume."
The virtualisation is done by Acopia's ARX intelligent network switch, he added. It means that while an application's data directory would still be allocated to hard disk, its working directory or its indexes could be placed on RAMdisk, without the application knowing the difference.
Cooper added that in the past you needed to specify which files went on which tier, but Acopia's new software will automatically move frequently accessed data to the RAMdisk-based Tier 0.
Acopia said that in lab tests, when a specific application file set was served from Tier 0 instead of NAS, the application ran almost 30 times faster. The Tier 0 storage used for the test was a dual-processor server with 32GB of memory, costing under $10,000. It claimed Tier 0 could therefore be 300 times more cost-effective than NAS.
The company attributes the Tier 0 concept to Taneja Group analyst Brad O'Neill, who pointed out in an article that while ILM typically focuses on reducing storage costs by moving infrequently used data to cheaper storage, it could equally well work the other way around, by moving the most frequently accessed data to the fastest storage.
Of course, that's not so different from how Tier 1 high-end disk arrays are used today. The key, according to Acopia's international head Tim Pitcher, is that virtualisation allows you to treat those files that need to be stored on disk differently from ones that don't.
"This is not where data lives," he said, "it's a working storage - it's a similar concept to solid-state disks, but no-one else can do this our way." ®