File restore overview

Use the IBM Spectrum Protect recovery agent for efficient file restore operations and to minimize downtime by mounting snapshots to virtual volumes.

The IBM Spectrum Protect recovery agent can be used for the following tasks:

  • Recovering lost or damaged files from a backup
  • Mounting a virtual machine guest volume and creating an archive of the virtual machine guest files
  • Mounting database applications for batch reports

The virtual volume can be viewed by using any file manager, for example Windows Explorer. The directories and files in the snapshot can be viewed and managed like any other file. If you edit the files and save your changes, after you unmount the volume, your changes are lost because the changed data is held in memory and never saved to disk. Because the changes are written to memory, the IBM Spectrum Protect recovery agent can use a large amount of RAM when it is working in read/write mode.

You can copy the changed files to another volume before you unmount the volume.

The default read only mount option is the preferred method, unless a mounted volume must be writeable. For example, an archive application might require write access to the archived volume.

The IBM Spectrum Protect recovery agent mounts snapshots from the IBM Spectrum Protect server. In the IBM Spectrum Protect recovery agent GUI, click Remove to close an existing connection to the IBM Spectrum Protect server. You must remove any existing connection before you can establish a new connection to a different server or different node. Dismount all volumes before you click Remove. The remove operation fails if there are active mount and restore sessions in the mount machines. You cannot remove the connection to a server when you are running a file restore from that server. You must first dismount all virtual devices and stop all restore sessions before you disconnect from a server. If you do not do so, the connection is not removed.

You must unmount all virtual volumes before you uninstall the IBM Spectrum Protect recovery agent. Otherwise, these mounted virtual volumes cannot be unmounted after the IBM Spectrum Protect recovery agent is reinstalled.

Restoring file information for a block-level snapshot is a random-access process. As a result, processing might be slow when a sequential-access device (such as a tape) is used. To run a file restore of data that is stored on tape, consider moving the data to disk or file storage first. From the IBM Spectrum Protect server administrative command-line client (dsmadmc), issue the QUERY OCCUPANCY command to see where the data is stored. Then, issue the MOVE NODEDATA command to move the data back to disk or file storage.

Mounting a snapshot from the same tape storage pool by two instances of Mount can cause one of these results:
  • The second Mount instance is blocked until the first instance is complete.
  • Both mounts succeed, but the performance is poor.
When restoring data from a mirrored volume, mount only one of the disks that contains the mirrored volume. Mounting both disks causes Windows to attempt a resynchronization of the disks. However, both disks contain a different time stamp if mounted. As a result, all data is copied from one disk to the other disk. This amount of data cannot be accommodated by the virtual volume. When you must recover data from a volume that spans two disks, and those disks contain a mirrored volume, complete these steps:
  1. Mount the two disks.
  2. Use the iSCSI initiator to connect to the first disk.
  3. Use Windows Disk Manager to import this disk. Ignore any message regarding synchronization.
  4. Delete the mirrored partition from the first (or imported) disk.
  5. Use the iSCSI initiator to connect to the second disk.
  6. Use Windows Disk Manager to import the second disk.
Both volumes are now available.
Restriction: Do not change the IBM Spectrum Protect node password while running a file restore from snapshots stored in that node.

File restore guidelines

You can use the IBM Spectrum Protect recovery agent for efficient file restore and to minimize downtime by mounting snapshots to virtual volumes. File restore is supported from snapshots of NTFS, FAT, or FAT32 volumes.

The mount function cannot be used to mount a snapshot of partitions from a dynamic or GPT-based disk as a virtual volume. Only partitions from an MBR-based, basic disk can be mounted as virtual volumes. File restore from GPT, dynamic, or any other non-MBR or non-basic disk is possible by creating a virtual iSCSI target and using an iSCSI initiator to connect it to your system.

If you are running a file restore of data on dynamic disks, the snapshot must be mounted to a server that has the same version of Windows, or a newer version of Windows, as the node that created the snapshot. Files on the dynamic disk can be accessed indirectly by nodes that have older versions of Windows, by mapping a drive on the older nodes to a CIFS share where the snapshot is mounted.

Important: The ACL values associated with the folders and files that are restored in a file restore operation are not transferred to the restored files. To maintain ACL values, use the XCOPY command when copying files from the target.