DataCore is updating its SANsymphony software with block-level tiering to move cold data to less costly secondary storage.
In an IT Press Tour briefing, Alexander Best, DataCore senior director for product management, said that 90 percent of data in SANsymphony deployments is cold. When users access a LUN, a logical chunk of storage, the cold and hot data blocks are mixed. He noted that traditionally, a LUN could be optimized for either performance or capacity, but not both. SANsymphony v10, currently in preview, will include Adaptive Data Placement to fix this.
Best said: “We’ll compress stale data at the block level. It’s continuous real-time, auto-tiering with inline dedupe and/or compression.” This “overcomes the all-or-nothing dilemma of LUNs.”
The adaptive data placement software splits a virtual disk container into small chunks that can go anywhere. SANsymphony has various storage tiers and a background capacity-optimized tier contains deduplicated and compressed data. There are policies setting block access frequency cut-off points for deduplication and compression, with overall aggressive, normal, and lazy policies.
SANsymphony continuously tracks data access frequencies (temperatures) and moves colder data from any tier to the capacity-optimized tier as per chosen policy. Based on ongoing access frequency, it can dynamically relocate data to the appropriate tier in real time, including tiering to/from the capacity-optimized tier.
Best claimed the approach is unique and allows for the optimization of both performance and cost (capacity). It may be unique now, but it wasn’t a decade ago.
Back in 2010, Dell-acquired Compellent had FluidData storage which used block-level tiering. Compellent’s data progression technology tracked disk block activity and moved a block of data up and down storage tiers, from SSD through Fibre Channel, SAS, and SATA drive tiers. Each block had metadata associated with it. Dell acquired Compellent and in 2013 its FluidFS technology could run on demand, and move relatively inactive SLC flash data to MLC, then to and through disk tiers.
By 2017, the Compellent branding had been replaced by SC, and that brand and separate product line disappeared after 2018 when Dell unified its branding with a “Power” prefix and consolidated products. The FluidFS technology then faded from view.
