Tuesday, June 9, 2009

NAS backup today is done in one of two methods; either across the wire file system backup which encounters all the problems that any network based backup would plus the added weight of having to communicate via a NFS/CIFS protocol or they are backed up via NDMP directly to a locally attached tape or disk. While a local NDMP dump reduces the performance limitations of a traditional NAS, it does not address the issue that both methods encounter; requiring the use of the NAS head for the backup process.

Using the NAS head for backup that is already being taxed by storage IO performance requirements leads to either very slow backups, reduced storage IO performance or worst case, both. This results in the backup administrator having to design incredibly complex backup strategies to minimize the impact. It is important to know that even snapshots won't help. While snapshots are great for presenting a consistent image to the backup application, the management of those snapshots and the backup of those snapshots still has to be managed by the same NAS head.

With their new Backup Accelerator, Isilon has provided an option for their customers to have a dedicated node or set of nodes specifically to perform the backup function. This allows the other nodes to continue to service storage IO demands while the dedicated backup nodes deliver data to the backup target. While this would be a game changer for any other company this is merely Isilon, harvesting their investment in clustered storage and is more a logical evolution of their offering.

The Backup Accelerator has the bandwidth to drive today's high speed fibre tape drives. They are using a 1U Isilon node with 4 x 4Gbps Fibre Channel ports to connect to the tape library and the DDR InfiniBand cluster interconnect. They state that they can achieve 480MBps per Backup Accelerator node and as with any of their solutions, performance scales linearly as you add more nodes.