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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. The controller automatically reverts a hot spare only if the failed drive is replaced with a new drive in the same slot. If the new drive is not placed in the same slot, a manual Replace Member operation can be used to revert a previously commissioned hot spare.
4.5.6Enclosure Affinity
Enclosure affinity is used to set the preference for a hot spare to be used to rebuild a physical disk that resides in the same physical enclosure. This does not preclude the hot spare from being provisioned to a second enclosure if there are no other hot spares present. For example, if there are two enclosures and each enclosure has a hot spare with affinity set, then upon a drive failure the hot spare will be provisioned from the same enclosure as the failed drive.
4.5.7Battery Back-up of Controller Cache
4.5.7.1Battery Management
The transportable battery backup unit (TBBU) is a cache memory module with an integrated battery pack that enables you to transport the cache module with the battery in a new controller. The TBBU protects the integrity of the cached data on the PERC H800 adapter by providing backup power during a power outage. The battery backup unit (BBU) is a battery pack that protects the integrity of the cached data on the PERC H700 cards by providing backup power during a power outage. The battery provides up to 24 hours of backup power for the cache memory.
4.5.7.2Battery Learn Cycle
Learn cycle is a battery calibration operation performed by the controller periodically to determine the condition of the battery. This operation cannot be disabled.
The time frame for completion of a learn cycle is a function of the battery charge capacity and the discharge/charge currents used. For PERC H700 or H800 cards, the expected time frame for completion of a learn cycle is approximately seven hours and consists of the following parts:
•
•
Learn cycle discharge cycle: approximately three hours
Learn cycle charge cycle: approximately four hours
During the discharge phase of a learn cycle, the PERC H700 or H800 battery charger is disabled and remains disabled until the battery is discharged. After the battery is discharged, the charger is re- enabled.
4.6Physical Disk Hot Swapping
Hot swapping is the manual replacement of a unit in a disk subsystem while the subsystem is performing its normal functions. The following requirements must be met before hot swapping a physical disk:
•The system backplane or enclosure must support hot swapping.
•The replacement drive must be of the same protocol and drive technology. For example, only a SAS HDD can replace a SAS HDD; only a SATA SSD can replace a SATA SSD.
•The replacement drive must be of equal or greater capacity than the one it is replacing.
DELL PERC H700 and H800 Technical Guide | 18 |
