User guide

Recovering from Drive Failure
In any RAID 1 logical drive on the Smart Array 431 Controller having
N physical drives in the array (not including spare drives), the first N/2
physical drives are normally mirrored in consecutive order to the second
N/2 physical drives. When determining the order, number each drive in
the array by increasing IDs on the SCSI bus.
RAID 5 Logical Drives
■ can sustain a single drive failure. The logical drive will be in a
“regenerating” condition if one drive is failed.
■ will be in a “failed” condition if more than one drive is failed.
■ will be in a “rebuilding” condition if a previously failed drive has been
replaced and the replacement drive is rebuilding. The volume may also
be in a “rebuilding” condition following a drive failure if a spare drive
was previously assigned and is rebuilding.
In the event of a drive failure, if a spare drive is assigned and available, the
spare drive acts as an immediate replacement for the failed drive. Data is
automatically reconstructed from the remaining drive(s) in the volume and
written to the spare drive via the Automatic Data Recovery process. Once the
spare drive is completely built, the logical drive is again running at full fault
tolerance, and is then able to sustain another subsequent drive failure. Note,
however, that if another drive were to fail before the spare drive is completely
built, the spare drive cannot prevent failure of the entire logical drive. Also
note that it is also possible for non-correctable disk errors to prevent
completion of the Automatic Data Recovery process (discussed below).