Dell EMC H745P MX - Patrol Read; Physical Disk Failure Detection; Using Persistent Hot Spare Slots

Automatic replace member with predicted failure
A Replace Member operation can occur when there is a SMART predictive failure reporting on a physical disk in a virtual disk. The
automatic Replace Member is initiated when the rst SMART error occurs on a physical disk that is part of a virtual disk. The target disk
needs to be a hot spare that qualies as a rebuild disk. The physical disk with the SMART error is marked as failed only after the successful
completion of the Replace Member. This prevents the array from reaching degraded state.
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: To enable the automatic Replace Member, use the Dell OpenManage storage management application.
Patrol Read
The Patrol Read feature is designed as a preventative measure to ensure physical disk health and data integrity. Patrol Read scans and
resolves potential problems on congured physical disks. The Dell OpenManage storage management application can be used to start
Patrol Read and change its behavior.
The following is an overview of Patrol Read behavior:
• Patrol Read runs on all disks on the controller that are congured 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 any disks involved in any of the following operations:
– Rebuild
– Replace Member
– Full or Background Initialization
– CC
– RLM or OCE
NOTE
: By default, Patrol Read automatically runs every seven days on congured SAS and SATA hard drives. Patrol Read is
not necessary on SSD and is disabled by default.
For more information on Patrol Read, see the Dell OpenManage documentation at Dell.com/openmanagemanuals.
Physical disk failure detection
Failed physical disks are detected and rebuilds automatically start to new disks that are inserted into the same slot. Automatic rebuilds can
also occur with hot spares. If you have congured hot spares, the controllers automatically try to use them to rebuild failed physical disks.
Using persistent hot spare slots
NOTE
: The persistent hot spare slot feature is disabled by default.
The PERC 10 series can be congured so that the system backplane or storage enclosure disk slots are dedicated as hot spare slots. This
feature can be enabled using the Dell OpenManage storage management application.
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Features