Creating asynchronous replicas (on a second Xiotech SAN system) over the WAN using the TimeScale appliance is straightforward and fairly simple, although not quite as simple as the five-click process in Compellent. Given the additional complexity introduced by enabling the use of other SAN devices and server-attached storage, this is not unexpected, and in fact it makes the smoothness of the Xiotech process all the more admirable.

TimeScale also allows the administrator to schedule and create an unlimited number of snapshots for data or system recovery, using either virtual snapshots to reduce the storage footprint or full replicas of the original data. Snapshots can be one to many, many to one, or many to many, allowing multiple snapshots to be created in different places from a single original, or allowing multiple originals to be consolidated into a single storage system.

The Xiotech system with the TimeScale appliance offers a couple of features not available from Compellent, including the SSD drives and replication and mirroring with heterogeneous devices. It doesn’t have hardware-based ILM, and it's not quite as easy to use as the Compellent system, but it's an excellent choice for administrators aiming to reuse existing storage assets.

The fat middle

All three of the systems reviewed here will provide excellent service in a small to midlevel enterprise environment. They are inexpensive enough to be good starter systems, yet expandable enough to grow with a company’s data needs. And all combine good usability and strong performance.

The iQstor iQ2880 has a more limited feature set than the other two, but still enough for most purposes, and it comes at a very low price. The Xiotech Magnitude 3D system offers sophisticated features at a reasonable price, including the highest possible performance (thanks to the solid state disk option) and excellent replication functions that support any SAN or server attached storage, even from other vendors.

The Compellent Storage Center offers the greatest ease of use, as well as automated data migration capabilities, at a great price. In fact, Compellent's level of maturity, both in feature set and ease of use, places it alone at the pinnacle of midrange systems and even compares favorably with top-tier systems. That said, if you don't need automated data migration, the iQstor is the most affordable way to start. And Xiotech should get a close look from any shop looking for a SAN that plays well with existing storage.