Changed volume mount-paths

Edit online

If you change a volume mount point or drive letter or change the file server name, HSM for Windows™ reconciliation can be affected. You can mitigate many problems by creating hardware volume mappings, and prevent some problems by using unique file space names.

If you change a volume drive letter, mount point, or file server name, you can maintain HSM services by creating a hardware volume mapping. If you do not create a hardware volume mapping, reconciliation processing can delete migration copies in IBM® Storage Protect storage. If the drive letter, mount point, or file server name does not match the information on the IBM Storage Protect server, a reconciliation process marks a migration copy as obsolete. The obsolete object is deleted from IBM Storage Protect storage, subject to retention policy. A hardware volume mapping matches the old drive letter, mount point, or file server name with the new drive letter, mount point, or file server name. With a hardware volume mapping, a reconciliation process does not delete migration copies only because the drive letter, mount point, or file server name is changed.

A hardware mapping maintains HSM services for some changes to nested volumes. If you change only the drive letter or file server name, a hardware mapping continues HSM services. If you move a nested volume to another volume, a hardware mapping does not continue HSM services.

For example, assume that volume \\MYNODE\E$\nested is mounted into volume \\MYNODE\E$. Files are migrated from both volumes and reconciliation is configured for both volumes.

Assume that you change the drive E to F. Volume \\MYNODE\E$ is renamed to \\MYNODE\F$ and volume \\MYNODE\E$\nested is renamed to \\MYNODE\F$\nested. In this case, a hardware volume mapping continues HSM services, including accurate reconciliation.

Assume that you do not change drive letter E, but you move the nested volume into \\MYNODE\G$. The nested volume becomes \\MYNODE\G$\nested. In this case, a hardware volume mapping cannot maintain HSM services.

The second case can be mitigated with some planning. You can migrate the files of each volume to a separate file space on the IBM Storage Protect server. Reconciliation can then be limited to only this file space. In this case, the IBM Storage Protect server query, which is performed at the beginning of the reconciliation for a volume, does not return any objects from other volumes. The IBM Storage Protect server does not delete any objects in storage that are from other volumes.

Tip: You can manage which file spaces are used during reconciliation with the FILESPacelist option of the dsmhsmclc command or by using the Reconcile settings window of the HSM for Windows client GUI.

If a reconciliation process deletes objects from IBM Storage Protect storage, you can restore the files from backup copies that were created by the backup-archive client. You can restore the complete file, even if the migration copy was deleted from IBM Storage Protect storage.