Write-Back Caching Disabled
What Caused the Problem?
Write-back caching was disabled on one or more logical drives. This problem can occur for the following reasons:
Battery Failure
Below minimum capacity
Discharged upon initial deployment or because of multiple cache backups in a row
The cache size memory of the controllers are different
Cache Reconfiguration
A Cache Data-Restore operation is in progress, which interrupted the normal write-back caching process
The space in the cache backup device is insufficient for storing the cache
The Recovery Guru Details area provides specific information you will need as you follow the recovery steps.
Important Notes
When write-back caching is enabled when logical drives are configured, write-back caching improves I/O performance. When write-back caching is disabled, I/O performance to the logical drive or group of logical drives is seriously degraded.
The error triggers a critical event.
The controller is in the Notified state.
When write-back caching is enabled, the system transitions from Notified to Optimal after all logical drives configured to use write-back caching are restored.
When the system transitions from Notified to Optimal, an information MEL event is logged to show that all normal write-back caching capabilities are restored for all logical drives in the system.
While in the Notified state, a forced-disable of write-caching on any additional logical drives has no effect, and no state transition occurs.
Recovery Steps
IMPORTANT: If the Recovery Guru Summary area reports other problems, fix them first, and then return to this procedure.
1
Check the Summary area for a Battery Failure problem.
If...
Then...
The Summary area IS reporting a Battery Failure problem
Go to step 2.
The Summary area is NOT reporting a Battery Failure problem
Go to step 3.
2
Perform the following steps:
a
Fix the Battery Failure problem.
b
Return to this procedure.
c
Click the Recheck button to rerun the Recovery Guru.
If...
Then...
The Recovery Guru still reports the Write-Back Caching Disabled failure
Go to step 3.
The Recovery Guru no longer reports the Write-Back Caching Disabled failure
You have successfully completed the recovery procedure. No further action is necessary.
3
Check the Recovery Guru Summary area for a Cache-Size Mismatch problem.
If...
Then...
The Recovery Guru Summary area IS reporting a Cache-Size Mismatch problem
Go to step 4.
The Recovery Guru Summary area is NOT reporting a Cache-Size Mismatch problem
Go to step 5.
4
Perform the following steps:
a
Fix the Cache-Size Mismatch problem.
b
Return to this procedure.
c
Click the Recheck button to rerun the Recovery Guru.
If...
Then...
The Recovery Guru still reports the Write-Back Caching Disabled failure
Go to step 5.
The Recovery Guru no longer reports the Write-Back Caching Disabled failure
You have successfully completed the recovery procedure. No further action is necessary.
5
Check the Recovery Guru Summary area for a Cache Reconfiguration problem.
If...
Then...
The Recovery Guru Summary area IS reporting a Cache Reconfiguration problem
Go to step 6.
The Recovery Guru Summary area is NOT reporting a Cache Reconfiguration problem
Go to step 7.
6
Perform the following steps:
a
Fix the Cache Reconfiguration problem.
b
Return to this procedure.
c
Click the Recheck button to rerun the Recovery Guru.
If...
Then...
The Recovery Guru still reports the Write-Back Caching Disabled failure
Go to step 7.
The Recovery Guru no longer reports the Write-Back Caching Disabled failure
You have successfully completed the recovery procedure. No further action is necessary.
7
Check the Recovery Guru Summary area for a Cache Data-Restore in progress problem.
If...
Then...
The Recovery Guru Summary area IS reporting a Cache Data-Restore in progress
Go to step 8.
The Recovery Guru Summary area is NOT reporting a Cache Data-Restore in progress problem
Go to step 9.
8
Perform the following steps:
a
Fix the Cache Data-Restore in progress problem.
b
Return to this procedure.
c
Click the Recheck button to rerun the Recovery Guru.
If...
Then...
The Recovery Guru still reports the Write-Back Caching Disabled failure
Go to step 9.
The Recovery Guru no longer reports the Write-Back Caching Disabled failure
You have successfully completed the recovery procedure. No further action is necessary.
9
Check the Recovery Guru Summary area for an Insufficient Storage Capacity in Cache Backup Device problem.
If...
Then...
The Recovery Guru Summary area IS reporting an Insufficient Storage Capacity in Cache Backup Device problem
Go to step 10.
The Recovery Guru Summary area does NOT report an Insufficient Storage Capacity in Cache Backup Device problem
Do not continue with the remaining recovery steps and contact your Technical Support Representative.
10
Perform the following steps:
a
Fix the Insufficient Storage Capacity in Cache Backup Device problem first.
b
Return to this procedure.
c
Click the Recheck button to rerun the Recovery Guru. The failure should no longer appear in the Summary area. If the failure appears again, contact your Technical Support Representative.
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