Intel SASMF8I manual Redundancy and Error Handling

•User specified rebuild rate (% of system resources to use from 0-100%).

Warning: Exceeding 50% rate may cause operating system errors caused by waiting for controller access.

•Background operating mode can be set for rebuilds, consistency checks,and initialization (auto restarting consistency check on redundant volumes).

Redundancy and Error Handling

•Enclosure management support, including LEDs.

•Activity and fault indicators per drive, port selector (dual-port drives).

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

•Auto-detection of failed drives with transparent rebuild. Disk activity (I/O to the drive) must be present 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 overdrives use peer read mode.

•Smart Technology predicts failures of drives and electronic components.

•Commands are retried at least four times.

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

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

•Failures are logged in Intel® RAID Web Console 2; CIM, LEDs, and via alarm.

•Multiple cache options provide choice of speed, redundancy:

—Disk Write Cache: The data written / (done) signal is returned when data is written to the drive or only to the drive’s cache.

^On (default): Write back mode enabled. Faster, because it doesn't wait for the disk, but data will be lost if power is lost.

^Off: Write-through mode enabled. Slower, but ensures data is on the disk.

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

^On: Read Ahead mode enabled. Faster in data sequential read mode but slower in data random read mode.

^Off: Non-Read Ahead mode enabled. Always reads from the drive after determining the exact location of each read.

•Redundancy through:

—Configuration stored in nonvolatile RAM and on the drives (COD).

—Hot swap support.

3 Intel® RAID Controller SASMF8I Hardware Guide