ProLiant DL760 Generation 2 Server Maintenance and Service Guide

Media Module Removal and Replacement Procedures
Hot-Plug Hard Drive Replacement Guidelines
You should be able to hot-plug a drive during normal activity. Be aware, however, that
replacing a hot-pluggable disk drive will affect system performance and fault tolerance.
NOTE: Depending upon the 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 impact than if the array has only three logical drives.
Advanced Data Guarding
When a disk drive is hot-plugged, although the system is functionally operational, the disk
subsystem might no longer be fault tolerant. Fault tolerance will be lost until the removed
drive is subsequently replaced and the rebuild operation is completed. This procedure takes
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 array contents
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, you must follow these
guidelines:
• 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.
• Never remove a working drive when another drive has failed. Drives failed by the
controller are indicated by the amber Drive Failure LED on the drive tray. Permanent
data loss will occur if a working drive is removed while a failed drive is being replaced.
• Never remove a drive while another drive is being rebuilt. A drive’s Online LED
flashes green while it is being rebuilt. A replaced drive is restored from data stored on the
other drives.
• Never turn a disk enclosure off while the initiator or controller is powered on or
active. Doing so can cause the initiator or controller to mark the drives as “f ailed.” This
action can result in permanent data loss.
• If a drive is replaced while the system is off, rebuilding the replaced drive might be
necessary. Follow the instructions on the screen or the instructions outlined in the system
reference guide.
CAUTION: During the boot prompt, pressing the F2 key will cause permanent data loss to
the entire logical drive. Press the F2 key only if all of the drives have been replaced or if
complete data loss is required.
4-8 HP ProLiant DL760 Generation 2 Server Maintenance and Service Guide