About backup image restore sets

Backup images are displayed in the Backup, Archive, and Restore interface. These images correspond to Enterprise Vault file system data or Enterprise Vault SQL databases. The images that you select comprise a backup image restore set.

To perform an Enterprise Vault SQL database restore or a recovery with Point in time (PIT), first determine the time to which you want to restore or recover the database. Next, decide upon the group of backup images that need to be restored in a sequence to restore or recover the database. This group of backup images is called a backup image restore set. A backup image restore set consists of the following images:

Note:

Recovery is only possible with SQL differential (transaction log) backup images.

Full backup image: A restore set starts with a full backup image.
Cumulative backup image: Add the last, cumulative backup image to the set. Add this image if it occurred between when the full backup image was taken and the time you decided to perform the restore or recovery.
Differential backup images: Add the differential backup images that occurred between the last cumulative backup (or full backup if no cumulative backup happened) and the time that you decided to perform the restore or recovery. If you want to perform a recovery with PIT, then include the immediate differential image after the PIT in the restore set.

The following example demonstrates how to determine a backup image restore set in different use cases.

Table: Understanding which back up images to select for a restore demonstrates which backup images you would select to comprise a backup image restore set at any given time instance. Depending on the time you want to restore or recover the database, determines which backup images you must include in the backup image restore set.

Table: Understanding which back up images to select for a restore

Time instance	The backup images that comprise the backup image restore set
t1	Full backup
t2	Full + Differential 1 (PIT)
t3	Full + Differential 1
t4	Full + Differential 1 + Differential 2 (PIT)
t5	Full + Differential 1 + Differential 2
t6	Full + Differential 1 + Differential 2 + Differential 3 (PIT)
t7	Full + Cumulative
t8	Full + Cumulative + Differential 3 (PIT)
t9	Full + Cumulative + Differential 3
t10	Full + Cumulative + Differential 3 (SQL tail-log backup)

The following examples explain which backup images you must select in the Backup, Archive, and Restore interface:

Example 1:

To restore an SQL database to time instance t3, your backup image restore set must consist of the following backup images:
- The full backup image with the options Take database offline and Leave database Non-operational or Leave database Read-only enabled.
- The first differential backup image with the option Leave database operational enabled.
Example 2:

To recover an SQL database with PIT at time instance t8, your backup image restore set must consist of the following backup images:
- The full backup image with the options Take database offline and Leave database Non-operational or Leave database Read-only enabled.
- The last cumulative-backup image with the option Leave database Non-operational or Leave database Read-only enabled.
- The third differential backup image with the option Leave database operational and Point-in-time recovery enabled.
Example 3:

To recover an SQL database at time instance t10 which is after the last differential backup, you must use Microsoft's SQL tail-log mechanism. For more information about performing a tail-log backup, visit Microsoft's Web site and search for more information on this topic.

In this example the backup image restore set would include the following images:
- The full backup image with the options Take database offline and Leave database Non-operational or Leave database Read-only enabled.
- The last cumulative-backup image with the option Leave database Non-operational or Leave database Read-only enabled.
- The third differential backup image with the option Leave database operational and Point-in-time recovery enabled.
- Perform a tail-log backup. See Microsoft's Web site for instructions on how to perform this type of backup.