Users Guide

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.
Physical disk hot swapping
NOTE: Shared PERC 8 supports physical disk hot-swapping, however this should only be implemented for uncongured or failed
drives.
Hot swapping is the manual replacement of a disk while the Shared PERC 8 card is online and performing the normal functions. The
following requirements must be fullled before performing a hot swap of a physical disk:
• The replacement disk must be of the same protocol and disk technology. For example, only a SAS hard drive can replace a SAS hard
drive.
• The replacement disk must be of equal or greater capacity than the one it is replacing.
Shared PERC 8 card cache preservation
The Shared PERC 8 card is capable of preserving its cache in the event of a system power outage or improper system shutdown. The
Shared PERC 8 card is attached to a Battery Backup Unit (BBU) that provides backup power to transfer contents of the DRAM to the
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 indenitely. 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 ash 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 Ensure that all online physical disks are still connected.
2 Restore the system power.
3 Boot the system.
Virtual disks are automatically imported and preserved cache (if any) are ushed to the physical disks of appropriate virtual disks. If
preserved cache is still present, there could be situations preventing the ushing of preserved cache data.
NOTE
: For more information on recovering the cache data, see the Dell Chassis Management Controller for Dell PowerEdge
VRTX User’s Guide at Dell.com/poweredgemanuals.
NOTE: If there is preserved cache in Shared PERC 8, you can clear the preserved cache in the CMC. If there is no
preserved cache, this option is not displayed in CMC which indicates that the preserved cache data is recovered and written
to the physical disks successfully.
NOTE: If preserved cache is discarded, preserved cache data is not written to the physical disks. Ensure that the preserved
cache data is not critical before discarding.
Shared PERC 8 card features 19