HP ProLiant DL760 Server - Manual (Page 111)

5-8 Compaq ProLiant DL760 Servers User Guide
Compaq Confidential – Need to Know Required
Writer: Bryce Miller Project: Compaq ProLiant DL760 Servers User Guide Comments:
Part Number: 173774-001 File Name: f-ch5 Installing Hardware Options - Hot Pluggable.doc Last Saved On: 1/18/01 6:12 PM
Important Guidelines About Replacing Hot-Plug
SCSI Hard Drives
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, both 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 of an impact
than if the array has 3 logical drives.
When a disk drive is hot-plugged, although the system is functionally
operational, the disk subsystem may no longer be fault tolerant. Fault tolerance
will be lost until the removed drive is subsequently 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 should incur
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.
IMPORTANT: Perform disk drive replacement during low activity periods whenever
possible. In addition, a current valid backup of the logical drives in the array of the drive
being replaced should be available even if the drive replacement is being made during
server downtime.
When replacing hot-plug hard drives in a fault-tolerant configuration, these
guidelines must be followed:
■ Never remove a hot-plug drive if the Online LED indicator is green.
Replace a hot-plug hard drive only when the drive’s Fault LED indicator
is amber, indicating a failure.
■ Never remove more than one drive at a time. 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.