Intel SRCSATAWB manual Redundancy and Error Handling

Redundancy and Error Handling

•In-band and out-of-band SES2.

•Enclosure management support.

•Activity and fault indicators per drive.

•Drive coercion (auto-resizing to match existing disks).

•Auto-detection of failed drives with transparent rebuild. There must be disk activity (I/O to the drive) for a missing drive to be marked as failed.

•Auto-resume on reboot of initialization or rebuild (must be enabled before virtual disk creation).

•Smart initialization automatically checks consistency of virtual disks if there are five or more disks in a RAID 5 array, which optimizes performance by enabling read- modify-write mode. RAID 5 arrays of only three or four drives use Peer Read mode.

•Dirty cache LED plus error reporting for cache write to disk.

•Smart Technology predicts failures of drives and electronic components.

•Patrol Read checks drives and maps bad sectors.

•Commands are retried at least four times.

•Firmware provides best effort to recognize an error and recover if possible.

•Failures are logged from controller and drive firmware, and SMART monitor.

•Failures are logged in NVRAM, viewable from OS Event Log, Intel® RAID Web Console 2; CIM, LEDs, and via alarm.

•Multiple cache options allow configuration-specific performance optimization:

—Write-back. Faster because it does not wait for the disk but data will be lost if power is lost.

—Write-through. Usually slower but ensures data is on the disk.

—Read Ahead. Predicts next read will be sequential and buffers this data into the cache.

—Non Read Ahead. Always reads from the drive after determining exact location of each read.

—Adaptive Read Ahead. Reads ahead and caches data only if doing sequential reads.

—I/O setting. Determines whether read operations check the cache before reading from disks.

✧Cache I/O: Checks cache first, only reads disk if data is not in the cache.

✧Direct I/O: Reads data directly from disk. (not cache)

3 Intel® RAID Controller SRCSATAWB Hardware User’s Guide