Intel RS25DB080 Hardware User's Manual page 14

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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.
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Smart Technology predicts failures of drives and electronic components.
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Patrol Read checks drives and maps bad sectors.
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Commands are retried at least four times.
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Firmware provides best effort to recognize an error and recover if possible.
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Failures are logged from controller and drive firmware, and SMART monitor.
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Failures are logged in NVRAM, viewable from OS Event Log, Intel
Console 2, CIM, and LEDs.
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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
— Write-through: Usually slower but ensures data is on the disk.
— Read Ahead: Predicts next read will be sequential and buffers this data into
— Non Read Ahead: Always reads from the drive after determining exact location
— Adaptive Read Ahead: Reads ahead and caches data only if doing
— I/O setting. Determines whether read operations check the cache before reading
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Redundancy through:
— Configuration stored in non-volatile RAM and on the drives (COD).
— Hot-swap support.
— Optional battery backup for cache memory.
4
power is lost.
the cache.
of each read.
sequential reads.
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)
Intel® RAID Controller RS25DB080 Hardware User's Guide
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