Recovering data from a physical volume
This topic describes scenarios where data can be recovered from a damaged physical volume.
When the TS7700 detects damaged physical volumes, the automated read-only recovery process starts. The TS7700 detects that a physical volume is bad when the physical volume is being mounted for a back-end tape operation. If the physical volume is damaged, you can contact an IBM service representative and have the service representative manually place the volume in automated read-only recovery.
Many error events might be posted to the TS7700 Events Page during the recovery. If you are concerned about the progress of the recovery, contact a service representative to evaluate the progress.
For more information about automated read-only recovery, see the topic Automated read-only
recovery in the Related information section.
Note: A service representative can also
force a manual read-only recovering by marking a physical volume as "read_only". This operation
should be performed only by an IBM service representative.
Physical volume recovery scenarios
There
are four possible scenarios in which data recovery can be attempted
from a physical volume. They include:
- Read operations failures on a physical volume exceed the error threshold
- In this scenario, the physical volume can be mounted. The TS7700 recognizes that the volume requires read-only recovery and makes it eligible for automated read-only recovery.
- A permanent error occurs for the physical volume
- In this scenario, a permanent error such as failure to mount causes the physical volume to become eligible for automated read-only recovery.
- Physical damage occurs to the cartridge
- In this scenario, the cartridge that contains the physical volume is damaged to an extent that reinsertion into the library can cause the volume to become stuck in a drive. To resolve this condition and recover the virtual volumes on the cartridge, contact the IBM Support Center and request a Cognitive Support Platform (CSP) case number.
- Physical damage occurs to the physical volume
- In this scenario, only the physical volume is damaged (for example, the tape is broken) and the cartridge can be reinserted in the library without becoming stuck. Subsequent mount attempts fail and automatic read-only recovery is started for that physical volume.