Technical data

Using BACKUP
11.15 Backing Up User Disks
causes BACKUP to check the contents of the output specifier against the
input specifier after the files are written to the volume. The /LABEL
qualifier indicates the label of the tape.
2. If you are backing up a large disk, you may want to use several tape drives
for the backup. For example:
$ ALLOCATE MUA0:,MUA1:,MUA2: !
%DCL-I-ALLOC, MUA0: allocated
%DCL-I-ALLOC, MUA1: allocated
%DCL-I-ALLOC, MUA2: allocated
$ BACKUP/IMAGE/RECORD/NOASSIST/RELEASE_TAPE
_From: DKA100:
_To: MUA0:FULL02.SAV,MUA1,MUA2/LABEL=MNTH "
%MOUNT-I-MOUNTED, MNTH mounted on _MUA0:
%BACKUP-I-RESUME, resuming operation on volume 2
%MOUNT-I-MOUNTED, MNTH02 mounted on _MUA1:
%BACKUP-I-RESUME, resuming operation on volume 3
%MOUNT-I-MOUNTED, MNTH03 mounted on _MUA2:
$
In this example, the individual commands perform the following actions:
! Allocate the tape drives that will be used in the backup.
" Back up DKA100: to a save set. The /IMAGE qualifier indicates this
operation is an image backup. BACKUP begins writing data to a save
set on the tape in MUA0. If the tape in MUA0: becomes full, BACKUP
initializes the tape in MUA1: and continues writing the save set. The
tape in MUA1: gets the label MNTH02. If necessary, BACKUP also uses
the tape in MUA2.
The /RELEASE_TAPE qualifier dismounts and unloads an output tape
device after BACKUP writes the save set. The /RECORD qualifier records
the current date and time in the file header record of each file that is
backed up.
11.15.3 Performing Image Backups to Disk
As described in Section 11.2, an image backup of a disk provides you with an
exact logical copy of all the files on the disk. You should perform image backups
with no interactive users on the system because of open file considerations
(described in Section 11.15.1). Also, system performance can be affected during
the backup process, so it is best to schedule the backup during the least busy
times for your system. You can optimize the speed of the backup procedure
by ensuring that certain process and system parameters are set properly (as
described in Section 11.7).
How to Perform This Task
To perform an image backup to a disk, use the BACKUP command in the
following format:
BACKUP/IMAGE/RECORD input-device output-specifier/SAVE_SET
The /IMAGE qualifier identifies the backup operation as an image backup. The
/RECORD qualifier records the current date and time in the file header record of
each file that is backed up. This information is essential for future incremental
backups. The /SAVE_SET qualifier indicates that you are creating a save set on a
disk.
11–34 Using BACKUP