Automated tiered storage isn’t a new concept — it’s been in archiving systems (HSM) as well as various iterations of information (or data) lifecycle management for years. It refers to the process of moving data between different classes, or tiers, of storage without human intervention. Storage tiering has been a cost saving strategy, mostly, and has typically been implemented with Fibre Channel or SAS drives on one tier, SATA drives on a second tier, and tape (if present) on a third tier. Archive systems moved data off high-speed disk to slow disk or tape when it became inactive and brought it back when it was needed.
Recently, solid-state disk (SSD) created another storage tier and brought a new application to automated tiered storage. Instead of moving less active data to slower, cheaper storage, systems now move more active data to faster, more expensive storage. This new wrinkle kind of ups the ante for storage tiering as a technology. If you only half-filled the SATA drives in your archive tier, the result would be insignificant compared with the cost of leaving an SSD tier half-full. Since the activity profile for a given data set changes, it would need to be dynamically (and automatically) moved into and out of an SSD tier in order to utilize it — and this requires automated tiered storage.
Given the cost pressures on IT and the increasing interest in solid-state storage, storage tiering will probably find its way into more and more disk deals for VARs. And, automated tiered storage is a technology that will be included in many of these projects. There are several ways to implement an automated tiered storage system and companies offer products for each. In a future post, we’ll discuss these methodologies and some of the products that leverage them.
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