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Veritas NetBackup™ Snapshot Client Administrator's Guide

Last Published: 2019-06-28

Product(s): NetBackup (8.2)

Restoring the entire snapshot on UNIX

You can recover data from the disk snapshot in several ways, depending on your hardware configuration and the snapshot method that the policy used.

To restore the entire snapshot if the snapshot method was FlashSnap

Unmount the snapshot source (original file system) and the snapshot file system on the alternate client:
```
    umount original_file_system
    umount snapshot_image_file_system
```
To locate the file systems:
See Restoring individual files on UNIX.
Deport the snapshot on the alternate-client:
- Find the VxVM disk group:
```
      vxdg list
```
  The format of the disk group name is as follows:
```
      SPLIT-primaryhost_diskgroup
```
  If vxdg list does not show the disk group, the group might have been deported. You can discover all the disk groups, including deported ones, by entering:
```
      vxdisk -o alldgs list
```
  The disk groups in parentheses are not imported on the local system.
- Deport the VxVM disk group:
```
      vxdg deport SPLIT-primaryhost_diskgroup
```

Import and join the VxVM disk group on the primary (original) client:

      vxdg import SPLIT-primaryhost_diskgroup
      vxrecover -g SPLIT-primaryhost_diskgroup -m
      vxdg join SPLIT-primaryhost_diskgroup diskgroup

Start the volume and snap back the snapshot volume as follows, using the -o resyncfromreplica option:

          vxvol -g SPLIT-primaryhost_diskgroup start SNAP_diskgroup_volume
          vxassist -g SPLIT-primaryhost_diskgroup -o resyncfromreplica
            snapback SNAP_diskgroup_volume

To restore the entire secondary disk if the snapshot was made on an EMC, Hitachi, or HP disk array

WITH CAUTION, you can use hardware-level restore to restore the entire mirror or secondary disk to the primary disk.
If the disk is shared by more than one file system or VxVM volume, there may be unintended results. Read the following:
Warning:
Hardware-level disk-restore (such as with the symmir -restore command) can cause data loss if more than one file system or more than one VxVM volume shares the primary disk. The hardware-level restore overwrites the entire primary disk with the contents of the mirror disk.
This overwrite can be a problem if you attempt to restore a snapshot of one of the file systems or one of the VxVM volumes that share the same disk. The other file systems or volumes sharing the disk may have older data that you do not want to write back to the primary. When the hardware-level disk-restore takes place, the older data replaces the newer data on the primary disk.

See About restoring on UNIX.