Product Reviews

3ware has always been a dominant force in the ATA RAID controller market and was quick to bring this expertise to bear on the Serial ATA (SATA) interface. Its latest Escalade 9000 series consists of five members, offering from four to 12 SATA ports. On review is the Escalade 9500S-12, which supports RAID0, 1, 5, 10 and 50 arrays along with hot-standby. Drives can also be hot-swapped in the event of a failure, although JBOD configurations are no longer supported and won't appear as available units to the OS. 3ware now uses the concept of single disk units, which can take advantage of features such as caching.

A battery backup pack will be available in September, but the cards currently on sale don't support it. However, we were advised by 3ware that, if you require this, it will replace existing cards with the new models at no extra charge when they become available. The Escalade uses 3ware's own custom processor and brings into play the company's StorSwitch technology to improve performance. Originally called DiskSwitch when it was introduced, this replaces the shared bus used by most storage solutions and provides a dedicated channel to each SATA drive.

Installation is straightforward. The simple BIOS screen allows you to create, delete, modify or rebuild arrays, add a hot-standby drive to an existing array and designate drives

ADVERTISEMENT

that aren't part of an array as single-disk units to allow them to be used by the OS. 3ware's 3DM 2 software runs as a Windows service and allows the controller to be accessed locally and remotely via a browser. You can monitor controller and array status, display alarms and send warning emails to a single recipient. The Maintenance screen provides the same levels of access as the BIOS menu for array creation and deletion, or adding and removing hot-spares.

For testing we fitted the Escalade in a dual 1.7GHz Xeon system running Windows Server 2003, which was installed on a pair of 36GB Western Digital Raptor drives configured as a RAID1 mirror. We then attached a four-bay SATA drive enclosure courtesy of StorCase International. Using another quartet of Raptor drives we created a RAID5 array with hot-standby, which took a shade over an hour to initialise.

Using the open-source Iometer for performance testing, we saw impressive transfer rates of 128MB/sec for read operations on the RAID5 array using two workers, 64KB request sizes and ten outstanding I/Os. Rerunning the same test on the mirrored array returned 70MB/sec. More importantly, on both tests processor utilisation never went above 9 per cent. Single drive performance was measured at 53MB/sec, while four drives and workers saw this rise to 152MB/sec. We then reconfigured three Raptor drives as a software-based RAID5 array managed by Windows. Rerunning Iometer with two disk workers returned only 71MB/sec. The processors were clearly being hit harder, with utilisation now going up to over 16 per cent.

There's little to separate 3ware and Adaptec for performance, costs per SATA port are comparable and both offer some useful management tools. However, although 3ware can't match Adaptec's SATA port count, it does offer much better expansion options as its cache memory can be upgraded, and it will support a backup battery pack in the near future.