Hot-Plug Drive Replacement Guidelines; Hot-Plug Drive Replacement Precautions; Removal And Replacement Procedures - Compaq ProLiant 8000 Maintenance And Service Manual

Hot-Plug Drive Replacement Guidelines

You should be able to hot-plug a drive during normal activity. Be aware, however, that
hot-plugging a disk drive will affect system performance and fault tolerance.
NOTE: Depending upon your configuration, a drive failure and the subsequent rebuild process will cause
storage subsystem performance degradation. For example, the replacement of a single drive on an array
with 50 logical drives will have less impact than if the array has three logical drives.
When a disk drive is hot-plugged, although the system is functionally operational, the disk
subsystem may no longer be fault tolerant.
IMPORTANT: Perform a disk drive replacement during low activity periods whenever possible. In
addition, have a current valid backup available for the logical drives in the array of the drive being
replaced, even if drive replacement is being made during server downtime.

Hot-Plug Drive Replacement Precautions

Be aware of the following Compaq guidelines for safe hot-plug replacement:
I
Do not remove a degraded drive if any other member of the array is offline (the online
LED is off). No other drive in the array can be hot-plugged without data loss, unless
RAID 0+1 is used as a fault tolerant form. In this case, drives are mirrored in pairs. More
than one drive can fail and be replaced as long as the drive or drives they are mirroring are
online.
Refer to your Smart Array Controller user guide for information on fault tolerance
options.
I
Do not remove a degraded drive if any member of an array is missing (previously
removed and not yet replaced).
I
Do not remove a degraded drive if any member of an array is being rebuilt, unless the
drive being rebuilt has been configured as an online spare. The online LED for the drive
being rebuilt will flash, indicating that a replaced drive is being rebuilt from data stored on
the other drives.
NOTE: An online spare will not activate and start rebuilding after a predictive failure alert because the
degraded drive is still online. The online spare activates only after a drive in the array has failed.
I
Do not replace multiple degraded drives at the same time (for example, when the system is
off), or the fault tolerance may be compromised. When a drive is replaced, the controller
uses data from the other drives in the array to reconstruct data on the replacement drive. If
more than one drive is removed, a complete data set is not available to reconstruct data on
the replacement drive or drives, and permanent data loss could occur.
CAUTION: Fault tolerance will be lost until the removed drive is replaced and the rebuild
operation is completed (this will take several hours, even if the system is not busy while the
rebuild is in progress). If another drive in the array incurs an error during the period when fault
tolerance is unavailable, a fatal system error could result.. If another drive fails during this
period, the entire contents of the array will be lost.

Removal and Replacement Procedures 2-19