Technical Product Specification

RAID Functionality and Features Intel® RAID Controller RS2WC080 and RS2WC040 TPS
Revision 1.0
Intel Order Number E64400-001
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4.1.2 RAID Virtual Drive Status
Table 11 RAID Virtual Drive Status
Drive State Code Description
Optimal Optimal The drive operating system is good. All configured drives are online.
Degraded Degraded The drive operating condition is not optimal because one of the configured drives has
failed or is offline.
Offline Offline The drive is not available to the operating system and is unusable.
4.1.3 RAID Controller Drive Limitations
Only drives that comply with the SAS and SATA specification extensions are supported.
4.2 SAS Bus and ID Mapping
Devices on the SAS bus are persistently mapped based on a SAS address.
4.3 RAID Features
4.3.1 RAID Level Support
The supported RAID levels are summarized in the following table.
Table 12 Supported RAID Levels
RAID Level Description
RAID 0 Data is striped to one or more physical drives. If using more than one disk, each strip 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 distributed parity: Data is striped across the hard disks and the controller calculates
redundancy 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 more RAID 1 arrays. Missing data is rebuilt
from redundant data strips. RAID 10 requires a minimum of four drives. RAID 10 provides high data
throughput rates.
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 strips. RAID 50 requires a minimum of six drives. RAID 50 provides high
data throughput rates
4.3.2 Cache Policies
The RAID cache can temporarily store data, so it can be more quickly accessed while it awaits
drive readiness. The cache is available both on the RAID controller and on hard drives. The
RAID controller’s read and write cache policy is set on a virtual drive level. This policy is set
when 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.