Technical data

Using BACKUP
11.1 Overview of BACKUP Tasks
11.1 Overview of BACKUP Tasks
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.
The two ways to back up your system disk are:
• Use the menu system described in Section 11.17.1.
• Use a special version of the OpenVMS Backup utility called standalone
BACKUP, described in Section 11.17.2. Use standalone BACKUP if you do
not have access to the OpenVMS VAX operating system distribution compact
disc.
Note
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.
Note
Some layered products have their own special backup procedures. For
more information, refer to the layered product documentation.
11–2 Using BACKUP