Managing file reconciliation
File reconciliation with IBM Storage Archive Enterprise Edition and considerations for the reconciliation process.
The reconciliation process scans for any inconsistencies that develop between files and file system objects (empty regular files, symbolic links and empty directories) in GPFS and their equivalents in LTFS. The number of unreferenced blocks on the tape is determined during the reconciliation process, and that is the reclaimable capacity of the tape.
Reconciliation can be performed on one or more GPFS file systems, one or more storage pools, or a set of tapes. When the reconciliation process involves multiple tapes, multiple IBM Storage Archive Enterprise Edition nodes and tape drives can be used in parallel. However, since recall tasks have priority, only available tape drives are used for reconciliation. Once reconciliation is started, the tape cannot be unmounted until the process completes.
Reconciliation considerations
- One process at a time: Only one reconciliation process can be started at a time. If an attempt is made to start a reconciliation process while another process is running, the attempt will fail. The eeadm tape reconcile command will fail and print the failure message to the screen.
- Preventing or waiting for migrations: When a reconciliation process is started, it reserves the tapes that it needs to reconcile. Migrations to those tapes are prevented until the reconciliation process completes, though migrations to other tapes can run in parallel. Options are available with the eeadm tape reconcile command to control reservation handling for reconciliation
- Holding recalls: Recalls from a tape being reconciled are not available while the reconciliation process is updating the index for that tape, which is a short step in the overall reconciliation process.