Controller cache preservation – Dell PowerEdge RAID Controller H800 User Manual
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Storage Controller Features
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 first SMART error occurs on a physical disk
that is part of a virtual disk. The target disk needs to be a hot spare that
qualifies 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
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:
To enable the automatic Replace Member, use the Dell OpenManage
storage management application. For more information on automatic Replace
Member, see "Dell OpenManage Storage Management" on page 81.
NOTE:
For information on manual Replace Member, see "Replacing an Online
Controller Cache Preservation
The controller is capable of preserving its cache in the event of a system
power outage or improper system shutdown. The PERC H700 controllers are
attached to a Battery Backup Unit (BBU) that provides backup power during
system power loss to preserve the controller's cache data. The PERC H800 has
a transportable version of the BBU attached to it called the Transportable
Battery Backup Unit (TBBU) which enables the entire cache module to be
transported to a new controller if necessary. If the card has the optional non-
volatile cache (NVC) or transportable non-volatile cache (TNVC) module,
the cache data is preserved using flash storage instead of battery power.
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