To stop the first phase of automatic backup, which is the backup
of the control data sets, you must use the STOP command.
You can use the following methods to interrupt automatic backup
processing during its last three phases. The last three phases of
automatic backup processing consist of the following functions:
- Movement of backup versions
- Backup of migrated data sets
- Backup of DFSMShsm-managed volumes having the automatic backup
attribute
There are four methods you can use to interrupt automatic backup
processing during its last three phases:
- Holding backup processing—You can
hold backup processing by specifying the BACKUP, BACKUP(AUTO), or
ALL parameter of the HOLD command. If you hold backup processing with
the ENDOFDATASET parameter while DFSMShsm is moving backup versions
or backing up migrated data sets, processing ends after DFSMShsm has
finished processing the current backup version. If you hold backup
processing with the ENDOFVOLUME parameter while DFSMShsm is moving
backup versions or backing up migrated data sets, processing ends
after the current phase of automatic backup has completed. If you
hold backup processing with the ENDOFVOLUME parameter while DFSMShsm
is backing up managed volumes, DFSMShsm continues processing the current
volumes and does not process any new volumes. Otherwise, DFSMShsm
finishes processing the current data set. DFSMShsm does not start
any new volume backup tasks.
- Disabling backup processing—You can
disable backup processing by specifying the NOBACKUP parameter of
the SETSYS command. If you disable backup processing while DFSMShsm
is moving backup versions or backing up migrated data sets, processing
ends after DFSMShsm has finished processing the current backup version.
If you disable backup processing while DFSMShsm is backing up DFSMShsm-managed
volumes, DFSMShsm finishes processing the current data set and does
not start any new volume backup tasks.
- Placing DFSMShsm in emergency mode—You
can place DFSMShsm in emergency mode by specifying the EMERGENCY parameter
of the SETSYS command. If you place DFSMShsm in emergency mode while
DFSMShsm is moving backup versions or backing up migrated data sets,
processing ends after DFSMShsm has finished processing the current
data set.
If you are in a multiple DFSMShsm-host environment and
have enabled the secondary host promotion function, another DFSMShsm
host takes over the unique functions of the primary DFSMShsm host
that you have put in emergency mode. Those functions include automatic
movement of backup versions from ML1 to tape, and automatic backup
of migrated data sets. If promotion occurs during an automatic backup
window (as defined on the primary host), and it is not past the latest
start time, the promoted host takes over where the primary host left
off. If the promoted host was an automatic backup host before being
promoted, it performs backups of DFSMShsm-owned volumes after performing
the automatic movement of backup versions from ML1 to tape, and automatic
backup of migrated data sets. If the promoted host was not an automatic backup host before being promoted, it does not
back up DFSMShsm-owned volumes.
If you place DFSMShsm in emergency
mode while DFSMShsm is backing up DFSMShsm-managed volumes, DFSMShsm
finishes processing the current data set before ending the volume
backup tasks that are in progress and does not start any new volume
backup tasks.
- Stopping DFSMShsm—You can stop DFSMShsm
by entering the MVS™ or DFSMShsm
STOP command. If you shut down DFSMShsm while DFSMShsm is moving backup
versions or backing up migrated data sets, processing ends after DFSMShsm
has finished processing the current data set. If you shut down DFSMShsm
while DFSMShsm is backing up DFSMShsm-managed volumes, DFSMShsm finishes
processing the current data set before ending the volume backup tasks
that are in progress and does not start any new volume backup tasks.
If you issue the DFSMShsm STOP command while DFSMShsm is backing up
the control data sets or the journal data set, DFSMShsm finishes processing
the current data set and does not start backing up any other control
data sets or the journal data set.
If you are in a multiple DFSMShsm-host
environment, have enabled secondary host promotion, and you have issued
a STOP PROMOTE command, another DFSMShsm host takes over the unique
functions of the primary DFSMShsm host that you have stopped. Those
functions include automatic movement of backup versions from ML1 to
tape, and automatic backup of migrated data sets. If promotion occurs
during an automatic backup window (as defined on the primary host),
and it is not past the latest start time, the promoted host takes
over where the primary host left off. If the promoted host was an
automatic backup host before being promoted, it performs backups of
DFSMShsm-owned volumes after performing the automatic movement of
backup versions from ML1 to tape, and automatic backup of migrated
data sets. If the promoted host was not an
automatic backup host before being promoted, it does not back up DFSMShsm-owned
volumes.
You can restart automatic backup processing by entering the corresponding
commands if certain conditions are met:
- RELEASE BACKUP or RELEASE ALL
- SETSYS BACKUP
- SETSYS NOEMERGENCY
- START DFSMSHSM (MVS command)
If secondary host promotion did not continue backup processing
where the primary DFSMShsm host left off, automatic backup restarts
at the point of interruption if the date of the defined start time
for the current automatic backup window is the same as the date that
automatic backup last started from the beginning (same cycle date).
When automatic backup restarts, it uses the same set of daily backup
volumes it was using when it first started. Those daily backup volumes
are the ones assigned to the day in the backup cycle that was in effect
when automatic backup started.
After you restart automatic backup processing, DFSMShsm continues
with the next DFSMShsm-managed volume under automatic backup control.
However, there are a few considerations:
- If you issued a DFSMShsm STOP command and then a START DFSMShsm
command, DFSMShsm can start automatic backup at the point of interruption
only:
- If you add the primary volumes under automatic backup control
in the same order in each startup of DFSMShsm
- If you do not change the volumes associated with the storage groups
- If you interrupted a BACKVOL PRIMARY command, DFSMShsm can resume
backup at the start of the next volume only if you issued HOLD BACKUP
or SETSYS NOBACKUP. You must issue RELEASE BACKUP, RELEASE ALL, or
SETSYS BACKUP during the same startup of DFSMShsm if you want the
BACKVOL PRIMARY command to resume processing.
- DFSMShsm does not restart a BACKVOL command issued for one volume.