Technical Product Specification

Intel® RAID Controller SRCSAS18E RAID Functionality and Features
Revision 1.01
Intel order number D61769-001
21
4.3 RAID Features
4.3.1 RAID Level Support
The following RAID levels are supported on the Intel
®
RAID Controller SRCSAS18E.
Table 12. RAID Levels
RAID Level Description
RAID 0 Data is striped to one or more physical drives. If using more than one disk, each stripe is stored on the
drives in a “round robin” fashion. RAID 0 includes no redundancy. If one hard disk fails, all data is lost.
RAID 1 Disk mirroring: all data is stored twice, making each drive the image of the other. Missing data on one
drive can be recovered from data on the other drive. RAID 1 requires two drives for each mirrored
array.
RAID 5 Data striping with parity: data is striped across the hard disks and the controller calculates redundacy
data (parity information) that is also striped across the hard disks. Missing data is rebuilt from parity.
RAID 5 requires a minimum of three drives in the array but can be expanded to the capacity of the
controller.
RAID 10 RAID 10 is accomplished by striping data across two or up to eight RAID 1 arrays. Missing data is
rebuilt from redundant data stripes. RAID 10 requires a minimum of four drives.
RAID 50 RAID 50 is accomplished by striping data across two or up to eight RAID 5 arrays. Missing data is
rebuilt from redundant data stripes. RAID 50 requires a minimum of six drives.
4.3.2 Cache Policies
RAID cache can be used to temporarily store data so it can be more quickly accessed, or to
await drive readiness. Cache is available both on the RAID controller and on hard disk drives.
The RAID controller read and write cache policy is set on a virtual drive level. This policy is set
at the time the virtual drive is created, but it can be changed using the Intel
®
RAID BIOS
Console 2 Configuration utility, the Command Line Utility, or the Intel
®
RAID Web Console 2
utility.