Midrange SANs with high-end features from Compellent, Xiotech
Multiple-tier storage, data migration jazz up these smaller systems, but ease of management sets them apart
Moving from one Magnitude storage tier to another, or from one RAID level to another, involves creating a second virtual disk, using the copy and mirror procedure to copy the first partition, and then breaking the mirror and attaching the second copy to the server in place of the first. This procedure is done fairly easily through the UI -- and without interrupting access to data. It is, however, a more involved process than with Compellent.
Expanding an existing virtual disk is fairly straightforward, as is setting up the snapshots and replication features. The Magnitude management interface is a multiple-tab affair; finding the necessary screen to configure any given feature by browsing through the tabs was usually easy.
Magnitude’s SAN map shows a physical map of the SAN, using a block diagram. It has excellent reporting tools that show environmental statistics, I/O by vdisk or RAID array, by drive shelf, or by physical or logical device. It also has a useful built-in Active Watch tool that will report any crossing of performance thresholds via e-mail or SNMP alarms.
I ran Intel IOmeter tests on both systems’ first- and second-tier storage volumes and found that Compellent Storage Center consistently ran about 20 percent faster than the Xiotech Magnitude system on both high-performance and SATA volumes. Tests were run from the same server, using the same HBA, with newly created volumes for each test. Coupled with the Compellent system’s higher total capacity -- it supports unlimited capacity, compared with Xiotech’s 19.2TB limit -- these performance numbers give Compellent a stronger leg to stand on.
That’s not to say that the Magnitude 3D 3000e System is a bad choice; it’s a well-engineered system that would look good in comparison to most other midtier SAN systems on the market. The Compellent system, however, is more mature and shows it. It offers automatic data migration, a cleaner, easier-to-use interface, and higher performance, all for about the same price per gigabyte.