The mmchdisk command
The mmchdisk command is issued when a failure that caused the unavailability of one or more disks has been corrected. The need for the command can be determined by the output of the mmlsdisk command.
The mmchdisk command performs four major functions:
- It changes the availability of the disk to recovering, and to up when all processing is complete. All GPFS utilities honor an availability of down and do not use the disk. recovering means that recovery has not been completed but the user has authorized use of the disk.
- It restores any replicas of data and metadata to their correct value. This involves scanning all metadata in the system and copying the latest to the recovering disk. Note that this involves scanning large amounts of data and potentially rewriting all data on the disk. This can take a long time for a large file system with a great deal of metadata to be scanned.
- It stops or suspends usage of a disk. This merely involves updating a disk state and should run quickly.
- Change disk attributes' metadata.
Subsequent invocations of the mmchdisk command attempts to restore the replicated data on any disk left in with an availability of recovering.
For more information, see mmchdisk command.