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Chapter 17. Forward recovery procedures
If a data set that is being used by CICS fails, perhaps because of physical damage
to a disk, you can recover the data by performing forward recovery of the data set.
About this task
Your forward recovery procedures can be based either on your own, or an
ISV-supplied utility program for processing the relevant CICS forward recovery log
streams, or you can use CICS VSAM Recovery. See CICS VSAM Recovery for z/OS
for details of forward recovery using CICS VR.
This section covers the following topics:
v “Forward recovery of data sets accessed in RLS mode”
v “Forward recovery of data sets accessed in non-RLS mode” on page 198
v “Procedure for failed RLS mode forward recovery operation” on page 198
v “Procedure for failed non-RLS mode forward recovery operation” on page 201
Forward recovery of data sets accessed in RLS mode
A recoverable data set that is updated in RLS mode can have retained locks held
for individual records.
In the event of a data set failure, it is important to ensure that you preserve any
retained locks as part of the data set recovery process. This is to enable the locks
associated with the original data set to be attached to the new data set. If the data
set failure is caused by anything other than a volume failure, retained locks can be
“unbound” using the SHCDS FRUNBIND subcommand. The data set can then be
recovered and the locks rebound to the recovered data using the SHCDS FRBIND
subcommand.
Note: If you use CICSVR to recover a data set, the unbinding and subsequent
binding of locks is handled by CICSVR. CICSVR also uses the SHCDS FRSETRR
and FRRESETRR commands to prevent general access to the data set during the
recovery process.
If a data set failure is caused by the loss of a volume, it is not possible to preserve
retained locks using FRUNBIND and FRBIND because SMSVSAM no longer has
access to the failed volume. When recovering from the loss of a volume, you can
ensure data integrity only by deleting the entire IGWLOCK00 lock structure, which
forces CICS to perform lost locks recovery. CICS uses information from its system
log to perform lost locks recovery. (For more information about lost locks
processing, see “Lost locks recovery” on page 89.) Recovering data from the loss of
a volume requires a different procedure from the simple loss of a data set.
The procedures to recover data sets that could have retained locks are described in
the following topics:
v For recovery of failed data sets where the volume remains operational, see
“Recovery of data set with volume still available” on page 188
v For recovery of failed data sets where the volume itself has failed, see “Recovery
of data set with loss of volume” on page 189.
© Copyright IBM Corp. 1982, 2010 187