Intel RS25NB008, Руководство пользователя

Страница: 14 / 52

4 Intel® RAID Controller RS25NB008 Hardware User’s Guide
•
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.
•
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, and LEDs.
•
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)
•
Redundancy through:
— Configuration stored in non-volatile RAM and on the drives (COD).
— Hot-swap support.
— Optional battery backup for cache memory.