Serial ATA Takes Aim at SCSI

With improved performance, reliability and capacity, Serial ATA RAID controllers are primed to replace SCSI in the workstation and small-server markets. eWEEK Labs believes IT managers should consider Serial ATA RAID technology when they are planning their next workstation or small-server purchases.

Our tests show that the current generation of Serial ATA hardware RAID controllers offers an impressive range of options. Controllers priced from $100 to $900 handle everything from desktops to small and midrange server tasks.

The key difference between less expensive Serial ATA cards and higher-priced high-performance cards is the inclusion of a RAID processor on the high-end hardware. Having an on-card RAID processor lets Serial ATA RAID controllers implement RAID without affecting CPU use of the server, although it also makes those cards much more expensive.

On the high end of the range is Applied Micro Circuits Corp.s 3Ware 9000 Series controllers. The 3Ware 9500S-8 Serial ATA 150 eight-port RAID Controller Card we tested is priced at $599, which is comparable to the Ultra SCSI cards it is designed to replace. (A 12-port version is available for $899, and a four-port version costs $399.)

In performance tests, the 3Ware 9500S-8 Serial ATA 150 card was speedy, able to write data at rates of up to 338MB per second on large-request, sequential-write tests.

This write performance is comparable to that of SCSI controllers, but Serial ATA hard drives are usually less expensive and more dense (theyre able to hold more data per hard drive) than SCSI technology.

Another eight-port Serial ATA RAID controller card that caught our eye was Broadcom Corp.s RAIDCore BC4852-H RAID controller. The RAIDCore BC4852-H is priced at $362, which makes it an excellent choice for IT managers grappling with tight budgets.

Click here to read more about Broadcoms RAIDCore BC4852-H controller.

Although Broadcoms RAIDCore BC4852-H is less expensive than Applied Micro Circuits high-performance 3Ware eight-port RAID controller card, the RAIDCore card has some innovative enterprise-class capabilities, such as Online Capacity Expansion, that are not available in the 3Ware 9000 series of cards. (Applied Micro Circuits officials said Online Capacity Expansion and other new capabilities will become available in a 3Ware 9000 firmware upgrade scheduled for later this summer.)

The RAIDCore BC4852-H can change the RAID level of a volume without forcing the IT manager to take it offline. This is an interesting feature that we normally see in more expensive cards, and it shows how enterprise-class capabilities are gradually trickling down to the small-business and workstation class of the market.

In tests, we saw throughput of 330MB per second from the RAIDCore BC4852-H. However, this solid performance came with added CPU usage—15.52 percent utilization compared with just 7.26 percent CPU utilization for the 3Ware 9500S-8 card.

Senior Analyst Henry Baltazar can be reached at henry_baltazar@ziffdavis.com.

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