Review: Adaptec Raid Series 2 Raid controller

Adaptec recently added a couple of new low-cost products to its line-up of unified serial adapters, designed specifically for use in entry-level servers and workstations.

Part of the Adaptec Series 2 Raid family, these enable small businesses to add support for hardware-based Raid using the same technology found on more expensive enterprise adapters, and to do so using both Serial Attached SCSI (Sas) and cheaper Serial ATA (Sata) disks.

There are two adapters to choose from: the Raid 2405 we were sent, which has four internal ports, and the Raid 2045 with four external interfaces. Both are low-profile (MD2) cards designed to be fitted into an x8 PCI Express expansion slot with a single small form factor connector for disk attachment.

Several cables are available to attach the disks to the card, ours shipping with an internal fan-out lead (included as part of the kit) to connect directly to four Sata/Sas disks. Others allow the card to be used with hard-wired backplanes and external storage enclosures, with support for enclosure management if required and up to 128 disks in total using cable expanders.

Sata/Sas tape drives can also be managed by the adapter, which offers up to 3Gbits/sec throughput using either technology. You can also mix Sata and Sas disks together, although overall performance is dictated by the slowest, and identical disks are recommended.

The driving force of the Raid 2045 is an 800MHz dual-core Raid-on-chip (Roc) processor, which is mounted in the middle of the adapter behind a large heatsink. There’s 128MB of DDR2 cache available to speed up disk writes and support for Raid Level 0 (disk striping), 1 (disk mirroring) and 10 (striping across multiple Level 1 arrays).

There’s no support for the more sophisticated Raid Level 5 arrays found on the high-end adapters, but you do get online capacity expansion, enabling extra disks to be added without having to recreate an array, plus hot-plugging and h ot-sparing. You also get ‘copyback hot sparing’, where the contents of a hot-spare disk are copied back to a later replacement automatically.

The installation procedure is much the same as for other Adaptec cards – fit the adapter, cable up the disks, then boot the server and use the onboard Bios utility to configure and format your arrays.

Alternatively, a copy of the Java-based Adaptec Storage Manager utility is included in the box, along with drivers to enable arrays to be accessed by all the leading operating systems, including Windows Server 2003/8, Red Hat and SUSE Enterprise Linux, and Sun Solaris 10.

It’s all pretty straightforward, but you need to make sure you have enough space for the disks, as entry-level servers are often restricted. We tested the adapter in a Dell Poweredge SC440, for example, which only had three available bays and no support for hot-swapping without taking the cover off.

Another consideration is that most small businesses looking for Raid will specify it as an option when ordering a new server. That said, there are good reasons for retro-fitting this kind of adapter.

For example, you may want to take advantage of the latest high-speed Sata/Sas storage technologies on older systems or improve performance and reliability by switching from software to hardware-based Raid. In which case, Adaptec’s new low-cost Series 2 controllers are hard to beat, offering the same single chip technology found on the company’s enterprise adapters in a package that won’t cost the earth.