Transtec Provigo 510 Business RAID

The Provigo 510 from Transtec shows why iSCSI is gaining ground over Fibre Channel in the SMB market, as it delivers a wealth of virtual storage at a price most FC SAN vendors can't match, let alone beat. And the company has made few sacrifices, as the 510 provides a pair of Gigabit ports for iSCSI target presentation, the full range of RAID support and plenty of storage capacity.

The 510 is essentially a VTrak M300i from Promise Technology. It employs a 2U rack chassis equipped with a dozen 500GB Seagate Barracuda SATA hard disks to provide a total of 6TB. Hardware functions have been separated into individual units accessible at the rear. You have a pair of 360W hot-swap redundant power supplies plus removable units for enclosure management, the RAID controller and the battery backup. The RAID module offers a pair of Gigabit iSCSI host ports plus Fast Ethernet and serial management ports, and also features a hardware TOE.

A CLI session can start the initial installation, but the interface isn't very intuitive. You can use the GUI instead, but we found the secure browser-based RAIDCentral tool more pleasant to use. This is nicely designed and makes it easy to access the controller, create logical drives and set up iSCSI targets.

There are plenty of drive-related options, and a wizard makes light work of configuration. With the manual option, you can create physical disk arrays and decide how many drives each contains. Next, you create up to 32 logical drives and choose from any supported RAID type for each one, along with cache policy and stripe size. The system was supplied with three RAID5 logical arrays spread across 11 drives with one kept back as a hot-spare. RAID6 support won't be implemented on this model until later this year. All logical drives appear under a single iSCSI node, so when you log an initiator on to the appliance it will see one target but all the logical drives.

To limit access to specific targets, you can use LUN mapping. Initiators are manually declared to the system and you provide a LUN number for the logical drives you want each one to access. Only those drives that have been declared to a host system will be seen, although any logical drives that haven't been assigned will show up as unknown in the Windows Disk Administrator.

To test performance, we used four Supermicro dual-core Xeon servers running Windows Server 2003 R2 and the Iometer utility. With one server logged on, we saw a sequential read throughput of 113MB/sec, and with a second server logged on to the other iSCSI port this rose to a cumulative 222MB/sec. The limitations of the two Gigabit ports were apparent when we had two servers logged onto each port, as Iometer returned a cumulative read throughput of 224MB/sec.

The Provigo 510 offers plenty of storage at a reasonable price and backs this up with good iSCSI performance. You don't get the level of performance offered by the Axstor Ai-Lite Ai-408, but if you want a high-capacity, low-cost IP SAN, choose the 510.

Author: Dave Mitchell