Users Guide
Auto replace member
The automatic Replace Member functionality allows a previously commissioned hot spare to be reverted to a usable hot spare. When a disk
failure occurs within a virtual disk, an assigned hot spare (dedicated or global) is commissioned and begins rebuilding until the virtual disk is
optimal. After the failed physical disk is replaced (in the same slot) and the rebuild is complete, the Shared PERC 8 card automatically starts
to copy data from the commissioned hot spare to the newly inserted disk. After the data is copied, the new disk is a part of the virtual disk
and the hot spare is reverted to a ready hot spare. This allows hot spares to remain in specic enclosure slots. While the Shared PERC 8
card is reverting the hot spare, the virtual disk remains optimal.
The physical disk with the SMART error is marked as Failed only after the successful completion of the Replace Member. This avoids
putting the array in degraded status. If an automatic Replace Member occurs using a source disk that was originally a hot spare (that was
used in a rebuild), and a new disk added for the Replace Member operation as the target disk, the hot spare reverts to the hot spare state
after a successful Replace Member operation.
NOTE: The Shared PERC 8 card automatically reverts a hot spare only if the failed disk is replaced with a new disk in the same
slot.
NOTE: A Replace Member operation typically has a temporary impact on disk performance. After the operation completes, the
disk performance returns to normal.
NOTE: To enable the automatic Replace Member, use the Dell OpenManage storage management application. For more
information about automatic Replace Member, see the topic Dell OpenManage Storage Management. For information on manual
Replace Member, see the topic Replacing An Online Physical Disk.
Patrol Read
The Patrol Read feature is designed as a preventive measure to ensure physical disk health and data integrity. Patrol Read scans for and
resolves potential problems on congured physical disks. The Dell Chassis Management Controller (CMC) can be used to start and control
the features of Patrol Read.
The following is an overview of Patrol Read:
• Patrol Read runs on all disks on the controller that are congured as part of a virtual disk, including hot spares.
• Patrol Read does not run on physical disks that are not part of a virtual disk or are in Ready state.
• Patrol Read adjusts the amount of controller resources dedicated to Patrol Read operations based on outstanding disk I/O. For
example, if the system is busy processing I/O operation, then Patrol Read uses fewer resources to allow the I/O to take a higher
priority.
• Patrol Read does not run on disks involved in any of the following operations:
• Rebuild
• Replace Member
• Full or Background Initialization
• Consistency Check (CC)
NOTE
: By default, Patrol Read automatically runs every seven days on congured SAS hard drives. Patrol Read is not necessary
on SSD and is disabled by default.
NOTE: In the event of a controller failover in systems with Fault Tolerant Shared PERC 8 card conguration, Patrol Read does
not continue on the active controller. You must start Patrol Read again through CMC. If you do not start Patrol Read, it
automatically starts on the active controller within seven days of the failover.
For more information on Patrol Read, see the Dell Chassis Management Controller for PowerEdge VRTX Online Help.
18
Shared PERC 8 card features