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Veritas NetBackup™ Administrator's Guide, Volume I

Last Published: 2017-09-25

Product(s): NetBackup (8.1)

Collect true image restore information (policy attribute) with and without move detection

The Collect true image restore information attribute specifies whether the policy collects the information necessary to perform a true image restore. A true image restore (TIR) restores the contents of a directory to reflect the contents of the directory at the time of an incremental or a full backup. Files that were deleted before the backup are not restored.

With the attribute enabled, a restore based on an incremental backup includes all files that were backed up since the last full backup. The restore also includes those files that were deleted at any time during that period.

NetBackup starts to collect the true image restore information with the next full or incremental backup for the policy. The true image restore information is collected for each client regardless of whether any files were changed.

NetBackup does not provide true image restores based on the time of a user backup or archive. However, NetBackup uses a user backup for a true image restore if the backup is more recent than the latest automatic full or incremental backup.

For true image incremental backups, enable With move detection to include the files that were moved, renamed, or newly installed in the directories. These files may be from a tar or a zip archive. (Depending on how the files were packaged and how they were installed, some newly installed files are not backed up by non-TIR incremental backups.

NetBackup detects changes by comparing path names and inode numbers with those from the previous full or incremental backup. If either the name or an inode number is new or changed, the file or directory is backed up. NetBackup begins to collect the information for move detection with the next full or incremental backup for the policy. This first backup after the attribute is set always backs up all files, even if it is an incremental backup.

Note:

With move detection must be enabled to create a synthetic backup.

See Synthetic backup (schedule attribute).

The following examples show how move detection backs up the files that otherwise would not be backed up:

On Windows:
- A file that is named C:\pub\doc is moved to or installed in C:\spec\doc. The archive bit is unchanged but C:\spec\doc is new in the C:\spec\ directory and is backed up.
- A directory that is named C:\security\dev\ is renamed as C:\security\devices\. The archive bit is unchanged but C:\security\devices\ is a new directory and is backed up.
On UNIX:
- A file that is named /home/pub/doc is moved to /home/spec/doc. The modification time is unchanged but /home/spec/doc is new in the /home/spec/ directory and is backed up.
- A directory that is named /etc/security/dev is renamed as /etc/security/devices. The modification time is unchanged but /etc/security/devices is a new directory and is backed up.
- A file that is named /home/pub/doc is installed when extracted from a UNIX tar file. The modification time is before the time of the last backup. The file is new in the /home/pub/ directory and is backed up.
- A file that is named docA is removed, then a file that is named docB is renamed as docA. The new docA has the same name but since its inode number has changed, it is backed up.

NetBackup begins to collect the information that is required for move detection with the next full or incremental backup for the policy. This first backup after the attribute is set always backs up all files, even if it is an incremental backup.

Move detection consumes space on the client and the backup can fail if there is not enough disk space available.