For BACKUP to effectively guard against data loss, you must
back up important data on a regular basis and be familiar with how
to restore the data when necessary.
Besides backing up your own files, directories, and disks,
you should also back up your system disk. If you have a standalone
workstation, backing up your system disk is probably your responsibility.
If your system is part of a large clustered computer system, an
operator or system manager is probably responsible for backing up
the system disk.
Use a special version of the OpenVMS Backup utility
called standalone BACKUP, described in
Understanding Standalone BACKUP (VAX Only). Use standalone BACKUP if you do not have
access to the OpenVMS VAX operating system distribution compact
disc.
Standalone BACKUP is not supported on OpenVMS Alpha
systems beginning with Version 6.1; you must use the menu system
provided on the distribution CD-ROM.
Performing an image backup using BACKUP also eliminates disk
fragmentation. Fragmentation can occur as you create and extend
files on a disk. If the file system cannot store files in contiguous
blocks, it stores them in noncontiguous pieces. Eventually, the
disk can become severely fragmented and system performance suffers.
To eliminate fragmentation, perform an image backup of the
disk and restore the backup copy. When you restore the image backup,
BACKUP places the files on the disk contiguously. Alternatively,
you can perform a disk-to-disk image backup without using the /SAVE_SET
qualifier. This creates a functionally equivalent copy of the entire
system disk, on which files are stored contiguously.
Some layered products have their own special backup
procedures. For more information, refer to the layered product documentation.
HP OpenVMS System Manager's Manual, Volume 1:... 
Using BACKUP
