Hardware User's Guide

4 Intel® RAID Controller RS2WC040 Hardware User’s Guide
Redundancy and Error Handling
• In-band SES2.
• Enclosure management support.
• Drive coercion (auto-resizing to match existing disks).
• Support the internal SAS Sideband signal SFF-8485 (SGPIO) interface.
• 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.
• 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.
• Cache options:
— Write-through: Usually slower but ensures data is on the disk.
— Normal Read: Always reads from the drive after determining exact location of
each read.
— Direct I/O: Reads data directly from disk without checking cache first.
• Access policy:
— RW: allow read and write I/O
— Read Only: allow read I/O only
— Blocked: deny read and write I/O
• Redundancy through:
— Configuration stored in non-volatile RAM and on the drives (COD).
— Hot-swap support.
SAS/SATA Features of the LSISAS2008 Controller
• Provides eight independent phys, each supporting 6 Gb/s and 3 Gb/s SAS data
transfers per PHY, only four phys are utilized by the RAID adapter.
• Supports SSP to enable communication with other SAS devices.