Intel raid controller srcsas144e - Manual (Page 12)

3 Intel® RAID Controller SRCSAS144E Hardware Guide
• 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, initialization
(auto restarting consistency check on redundant volumes), migration, OCE, and patrol
read.
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.
• Dirty cache LED plus cache write to disk error reporting.
• 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 from it if possible.
• Failures are logged from controller and drive firmware, SMART monitor, SAF-TE
controller.
• Failures are logged in NVRAM, viewable from OS Event Log, Intel ® RAID Web
Console 2; CIM, LEDs, and via alarm.
• Multiple cache options provide choice of speed, redundancy:
— Write: The data written / (done) signal is returned when data is written to drive or
only to cache:
^
Write-back (default): Faster, because it since doesn't wait for the disk, but
data will be lost if power is lost.
^ Write-through: Slower, but ensures data is on the disk.
— Read Ahead: Predicts the next read will be sequential and buffers this data into
the cache:
^
NonRead Ahead: Always reads from the drive after determining the exact
location of each read.
^ Adaptive Read Ahead: Will read ahead and cache data only if doing
sequential reads.