Controller Cache Preservation; Battery Transparent Learn Cycle - Dell PowerEdge VRTX User Manual

begins rebuilding until the virtual disk is optimal. After the failed disk is replaced (in the same slot) and the rebuild to the
hot spare is complete, the controller 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 being a
ready hot spare. This allows hot spares to remain in specific enclosure slots. While the controller is reverting the hot
spare, the virtual disk remains optimal.
NOTE: The controller 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.

Controller Cache Preservation

The controller is capable of preserving its cache in the event of a system power outage or improper system shutdown.
The Shared PERC 8 controller is attached to a Battery Backup Unit (BBU) that provides backup power to transfer
contents of the DRAM to Non-Volatile Cache (NVC) during system power loss.
Cache Preservation With Non-Volatile Cache
The Cache Preservation With Non-Volatile Cache (NVC) module allows controller cache data to be stored indefinitely. If
the controller has data in the cache memory during a power outage or improper system shutdown, a small amount of
power from the battery is used to transfer cache data to a non-volatile flash storage where it remains until power is
restored and the system is booted.
Recovering Cache Data
If a system power loss or improper system shutdown has occurred:
1. Restore the system power.
2. Boot the system.
3. Ensure all online physical disks are still connected.
4. Access the Dell Chassis Management Controller (CMC) to discard pinned cache.
If you do not see the Discard Pinned Cache option, it indicates that all preserved cache data is written to the disks
successfully.
NOTE: If there is pinned cache in Shared PERC 8, the option to clear the pinned cache is present in the CMC. If
there is no pinned cache, this option is not displayed in CMC and this indicates that the cache data is
recovered.
NOTE: For detailed navigation of the CMC for Shared PERC 8, see the
Dell PowerEdge VRTX User's Guide at dell.com/esmmanuals.

Battery Transparent Learn Cycle

A transparent learn cycle is a periodic operation that calculates the charge that is remaining in the battery to ensure
there is sufficient energy. The operation runs automatically, and causes no impact to the system or controller
performance. The controller automatically performs the Transparent Learn Cycle (TLC) on the battery to calibrate and
gauge its charge capacity once every 90 days. If required, the operation can be performed manually.
NOTE: Virtual disks stay in Write Back mode, if enabled, during transparent learn cycle. When the TLC completes,
the controller sets the next TLC to +90 days.
Dell Chassis Management Controller for
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