Technical data

Using BACKUP
11.16 Restoring User Disks
Note
Renaming directories is not recommended. Also, changing security
information for a directory changes its modification date. Thus, a
directory might appear to be ‘‘renamed’’ and its contents included in
incremental save sets if the file protection or security information is
changed. The addition of renamed directory contents might increase the
size of some incremental save sets.
BACKUP processes the target disk directory structure by directory levels, in
alphabetical order. Thus, circumstances can occur that prevent BACKUP from
correctly restoring an incremental save set to a target disk. For example, the
target disk does not have sufficient space to hold newly ‘‘renamed’’ directories and
their contents prior to deleting the original directories and their contents on the
target disk.
If incremental restore fails due to insufficient disk space, a possible solution is to
apply the incremental save set a second time (before doing anything else). This
causes the first incremental restore to continue and delete directories and their
contents, making more space available on the target disk. A second solution is to
selectively restore files from the save set.
BACKUP attempts to restore alias or synonym file entries in incremental restore
operations that do not specify multiple processing of alias or synonym file entries
(/NOALIAS). In cases where the alias entry cannot be restored properly, BACKUP
issues an error message indicating the alias file entry, its primary file, and a
secondary status of the cause of the failure.
If you specify the /LOG qualifier, then BACKUP issues a message upon successful
restoration of alias file entries.
If you specify the /VERIFY qualifier, BACKUP attempts alias entry restoration
during the verify pass. Otherwise, alias entry restoration is attempted along
with the normal file restoration. The reason for this behavior is that BACKUP
attempts to restore all primary files before attempting to restore alias entries that
will eventually reference those files.
11.16.3 Restoring Volume Shadow Sets
Because of the way volume shadowing duplicates data on each disk in the shadow
set, there are special considerations for restoring a shadow set. To restore a
shadow set, refer to Volume Shadowing for OpenVMS.
Note
Because the BACKUP output device (the shadow set) must be mounted
using the /FOREIGN qualifier, Compaq does not support a restore
operation from an image save set to a virtual unit.
11–50 Using BACKUP