Specifications

Recovering from Hard Drive Failure
86 MSA1000 Reference Guide
If another drive in the array should fail while you are rebuilding a previously
failed drive, then fault tolerance has been compromised and all data on the array
will be lost, with the following exceptions:
■ In a mirrored (RAID 1) configuration, failure of a drive that is not mirrored to
any other failed drives.
■ A second drive failure in a RAID ADG configuration.
Take these precautions when removing failed drives to minimize the likelihood of
compromising your logical drive data:
■ Do not remove a degraded drive if any other member of the array is off-line
(the online indicator is off).
■ Do not remove a failed second drive from an array until the first failed or
missing drive has been replaced and the rebuild process is complete. (When
the rebuild is complete, the online indicator on the front of the drive will stop
blinking.) Exceptions include RAID ADG configurations, as any two drives
in the array can be replaced simultaneously.
When a hard drive is replaced, the controller uses fault tolerance data on the
remaining drives in the array to rebuild data (previously on the failed drive) onto
the replacement drive. If more than one drive is removed at a time, the fault
tolerance data is incomplete. The missing data cannot then be reconstructed and is
likely to be permanently lost.