Monday, July 18, 2011

An example of a product closing these gaps and making disk backup even more appealing is the ExaGrid EX13000E. ExaGrid claims that in a single 3U appliance they can ingest 2.4TB per hour and store a 13 TB full backup plus up to 4 months worth of copies of that 13 TB. The effective backup capacity that a customer will typically see when factoring in deduplication and compression could be as high as 260 TB. This is the result a typical medium sized business should see when performing a weekly full, daily incremental rotation strategy over the course of four months. Of course your milage will vary and the length of time you want to retain data on disk will impact sizing as well.

The key of all the ExaGrid solutions is that they use a grid architecture to expand their capacities. This allows up to 10 nodes to be joined and managed as if they were one entity. At first glance the ExaGrid cluster is what we typically call a loosely coupled cluster in that data is written into a single node and not across all nodes in the cluster. The advantage of that strategy is that you can start with just one node for an initial implementation and you can easily mix and match generations of nodes over time.

The reality is though that the ExaGrid architecture is more sophisticated than a simple loosely coupled cluster. ExaGrid’s ability to provide a unified management layer and the fact that any node can get to a virtual pool of storage, we have been convinced to give the ExaGrid a “moderately coupled cluster” moniker.

The only downside to loosely coupled clusters, at least in this use case, is that for a single backup job/stream you are limited to the performance of a single node. For ExaGrid’s target market, the medium sized enterprise, that 2.4TB per hour transfer rate is going to be more than sufficient.

Storage Swiss Take

Thanks to the density of the system and aggressive pricing the EX13000E brings a new price point to disk based backup systems. ExaGrid has a mature deduplication and replication feature set and the grid architecture eliminates the need for expensive forklift upgrades or the expense of having to manage multiple independent systems. Another important factor is that ExaGrid has been focused on the backup deduplication market for years now, it is a stable company that is heading in the right direction. Just the kind of place where you want to place company long term assets.

George Crump, Senior Analyst