Considerations for using fileset backup with IBM Storage Protect

IBM Storage Protect stores backup data that is indexed by file or directory object path names in its database. However, file system objects are identified for IBM Storage Protect by their object ID extended attributes. In both cases, IBM Storage Protect is not aware of the fileset entity. Therefore, the fileset configuration of an IBM Storage Scale cluster is neither backed up nor it can be restored by IBM Storage Protect alone, unless separate action is taken.

IBM Storage Scale does provide commands such as mmbackupconfig and mmrestoreconfig to backup and restore file system configuration data.

Even though backups of independent filesets might be stored on a plurality of IBM Storage Protect servers, IBM Storage Protect for Space Management can only utilize one server per managed file system if mmbackup is used on that file system and sends the backup data to that same server. IBM Storage Protect for Space Management multiserver feature is not integrated with the mmbackup command.

If space management is enabled for an IBM Storage Scale file system, and a plurality of IBM Storage Protect servers are used for backup, the following limitations apply to the use of IBM Storage Protect for Space Management:

  • The setting of migrequiresbkup cannot be utilized since the server for space management might not have access to the database for the server doing backup on a particular object.
  • The inline copy feature that allows the backup of a migrated object through copying data internally from the IBM Storage Protect for Space Management pool to the backup pool inside the IBM Storage Protect server cannot be used since migrated data might reside on a different server than the one performing the backup.

The following special considerations apply when using the fileset backup with IBM Storage Protect:

  • IBM Storage Protect Backup-Archive client does not restore fileset configuration information. Therefore, a full file system backup is not sufficient for disaster recovery when the whole file system structure needs to be recovered.

  • Nested independent filesets cannot be backed up when using the fileset backups. Resolve the nesting before starting to protect the data with mmbackup on each fileset.

  • The following operations are discouraged: fileset unlink, fileset junction path change via unlink and link operations, fileset deletion. These operations will incur a heavy load on the IBM Storage Protect server at the next backup activity due to the significant alteration of the path name space that result from these operations. If a fileset must be moved in the file system, be prepared for the extra time that might be required to run the next backup.

  • If only utilizing fileset backup, be sure to include every fileset, including the root fileset to ensure complete data protection.

  • When both file system and fileset backups use the same IBM Storage Protect server, new and changed files may be unintentionally backed up twice. This consumes two of the file versions stored in the IBM Storage Protect server with the same file data.

    Loss of data protection may occur if a fileset is unlinked or deleted for an extended period of time and the objects formerly contained in that fileset are allowed to expire from the backup sets.

  • Do not move, rename, or relink a fileset, unless a new full backup of the fileset is expected to be made immediately after the restructuring occurs. IBM Storage Protect server only recognizes objects in backup only as long as they remain in their original path name from the root of the file tree (mount point).

The following special considerations apply when using fileset backup and IBM Storage Protect for Space Management:

  • When using fileset backup to different IBM Storage Protect servers, the server setting migrequiresbkup must be set to NO to be able to migrate files.

  • Automatic server selection for backup by mmbackup is not supported and therefore the IBM Storage Protect multiple space management server feature is not integrated with mmbackup data protection of IBM Storage Scale. Using fileset backup to different IBM Storage Protect servers in conjunction with the multiple space management server feature requires special handling and configuration because backup and space management rules must match so that files are handled by the same IBM Storage Protect server.