SNW At SNW in Dallas Compellent has become the first storage array vendor to follow EMC's lead and add solid state storage (SSD) to its product line. It has also added automatic cut-over to a remote site following server failover.
Compellent's storage area network (SAN) arrays sell to mid-range enterprises. Its controlling software tracks disk block use and moves chunks of data between storage tiers, depending on access patterns. SSDs are another storage tier and Compellent's software will automatically move blocks to and from the SSD tier 0, as it does already between other tiers. It isn't disclosing its supplier, but the SSDs will have Fibre Channel (FC) interfaces. This suggests STEC, EMC's SSD supplier, as it's the only such firm known to have them.
Customers with transactional databases who need higher performance are identified as potential users. The SSDs won't be cheap and the higher transaction performance will have to deliver sufficient benefits to make the SSD cost worthwhile.
Several existing Compellent users are beta-testing the SSDs, with general availability expected in Q1 2009. Compellent will then be the only SSD-using alternative to EMC's SDD-enhanced CLARiiON products, and will give 3PAR, HDS, HP, IBM, Pillar, Sun and other storage suppliers something to think about.
Compellent has revealed that its six-month roadmap contains a feature for customers who have two Compellent SANs in separate data centres with one designated as a primary site. The two SANs become a kind of single mirrored SAN. Data is replicated at block level from the primary to the secondary SAN. If there is a change in access patterns, such that servers in the secondary site now access the SAN because of a disaster or planned cut-over for whatever reason, then the secondary SAN automatically becomes the primary one and the replication data flow is reversed. When the original primary site servers are reinstated, so is the original primary SAN and the data flow reverses once more.
The replication between the two sites is asynchronous. Before the cutover to the secondary SAN a snapshot is taken of the primary SAN. This means there's a risk from that point to the secondary SAN of a loss of data as it comes online. Compellent says that Live Volume "is more than good enough" for its customers. It says mid-sized enterprises will welcome it because it adds a new feature they can use, and larger customers will like it because they don't have to buy separate mirroring or replication products.
Compellent is adding performance with the SSD technology, and protection against downtime with its Live Volume replication technology. It's extending he block-level metadata it maintains and uses to move data between storage tiers to provide data movement between SAN locations as needed. It ties in with server virtualisation as it virtualises the SAN location.
Live Volume will be made available in the second quarter of 2009 - with at least five months before delivery. ®