Overland Storage REO Series RA2000 review

To test the appliance we initially installed the iSCSI initiator software on a dual 1.7GHz Xeon server running Windows Server 2003 and logged on to a single iSCSI target drive. Using the open-source Iometer performance utility we assigned one disk worker to the drive. Utilising 64KB transfer requests and a 100 per cent sequential distribution we saw an average transfer rate of 33MB/sec. We then brought in three more servers using their own iSCSI targets and ran separate instances of Iometer, which reported a cumulative transfer rate of 99MB/sec. During this test we noted that processor power has a significant impact on throughput due to the demands of the iSCSI software - you can see these results in our review of Adaptec's iSCSI HBA (see p168). For the final test we configured four iSCSI targets on the dual Xeon server as a RAID-0 striped array and used the same Iometer configuration but with four disk workers assigned to the array and ten outstanding I/Os selected. Although this only returned 66MB/sec, it's worth noting that this is about 25MB/sec faster than the server's local Ultra320-based storage could deliver.

Our tests results show that iSCSI doesn't even come close to FC SANs for performance as revealed all too clearly by the Chaparral RIO eXp. However, its biggest strength is the much lower cost of implementation. As a backup accelerator, the REO RA2000 certainly delivers on its promise, which is precisely why our last backup tape drive group test used it as the main test platform.

Author: Dave Mitchell