Xserve RAID Card (Xserve Early 2009)

Enhance storage performance and data protection by configuring your system with the Xserve RAID Card and multiple SAS or SATA hard drives. The Xserve RAID Card replaces the built-in SATA/SAS controller board and does not use a PCI Express slot. Please note that your Xserve must have either all SATA or all SAS drives in drive bays 1 through 3.

Coupled with two or more hard drives, the Xserve RAID Card offers improved performance and data protection to your Xserve system — up to 497MB/s in RAID 0 and 330MB/s in RAID 5 of sequential read performance. This hardware RAID option supports RAID levels 0, 1, 5, and Enhanced JBOD and has 512MB of cache. It features an integrated 72-hour battery backup for protecting the RAID cache. The card replaces the built-in SATA/SAS controller and does not use a PCI Express slot.
System Requirements
Requires Xserve (Early 2009)
To enable your Xserve for hardware RAID, install the Xserve RAID card and two or more drives of the same type in bays 1 through 3. Each RAID level has minimum requirements for the number of hard drives:

RAID Level Drive Requirements Benefit
Enhanced JBOD One drive Single boot drive
RAID 0 (striping) Two or three hard drives Maximum performance and capacity
RAID 1 (mirroring) Two hard drives Maximum protection for critical data
RAID 5 Three hard drives Protection and performance; ability to survive a single disk failure; efficient capacity utilization

The Xserve RAID Card supports the creation of multiple RAID sets in a system and multiple volumes per RAID set. For optimal disk utilization in a RAID set, all hard drives should be the same size and must be the same type (SATA or SAS). Using Apple's RAID Utility software (included with Mac OS X Server v10.5), you can migrate the boot drive into a RAID set without reinstalling or reformatting the drive, and you can customize your RAID volumes to meet your exact requirements.