User guide

Compaq StorageWorks RAID Array 4000 User Guide
Failed drives in hot-pluggable trays can be removed and replaced while host
system and storage system powers are both on. Of course, hot-pluggable
drives can also be replaced when the power is off. Remember, however, to
NEVER TURN OFF the RA4000 while the host system power is on. This
would result in the failure of all drives in the storage system, which would
likely compromise your fault tolerance. When a hot-pluggable drive is
inserted, all disk activity on the controller will be temporarily paused while the
drive is spinning up (usually 20 seconds or so). If the drive is inserted while
power is on, in fault tolerant configurations, recovery of data on the
replacement drive will automatically begin (indicated by a blinking
online LED).
The capacity of replacement drives must be at least as large as the capacity of
the other drives in the array. Drives of insufficient capacity will immediately
be failed by the controller without starting Automatic Data Recovery.
If the RA4000 has failed a drive, replace the drive with a new or
known-good replacement drive. In some cases, a drive that has previously failed
by the controller may appear to be operational after the system is power-cycled,
or after removal and reinsertion of a hot-pluggable drive. However, this practice
is highly discouraged as use of such “marginal” drives may eventually result in
data loss.
If a drive in a fault-tolerant configuration is replaced while the system power
is off, the controller will display a Power-On Self-Test (POST) message
during the subsequent system startup. This indicates that the replacement drive
has been detected and that Automatic Data Recovery may need to be started.
Press F1 to initiate the background Automatic Data Recovery process. If
Automatic Data Recovery is not enabled, the logical drive will remain in a
ready to recover condition and the same query will be displayed at the next
system restart.
Replacement drives are not considered to be online until Automatic Data
Recovery is completed, at which time the online LED stops blinking and is on
steadily. Any drives that are not yet online are treated as if they are failed
when trying to determine whether fault tolerance will be compromised. For
example, in a RAID 5 logical drive with no spare and one drive rebuilding,
another drive failure at this time would result in a failure condition for the
entire logical drive.