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INQUIRE DSNAME command returns values from the VSAM base cluster block
(BCB). However, because base cluster block (BCB) recovery values are not set until
the first open, if you issue an INQUIRE DSNAME command before the first file is
opened, CICS returns NOTAPPLIC for RECOVSTATUS.
BDAM files
You can specify CICS support for backward recovery for BDAM files using the
LOG parameter on the DFHFCT TYPE=FILE macro. You can also specify that you
want automatic journaling of the various types of file access, using the JREQ and
JID parameters of the FCT macro.
LOG=YES
If you specify LOG=YES, CICS provides backout recovery for the file. Using
the services of the CICS recovery manager and log manager, CICS file control
writes before-images of updated records to the system log stream.
JREQ=request-type(s) and JID=nn
Specify the file requests that you want CICS to journal automatically to the log
stream mapped by the journal identifier specified on the JID parameter.
Although CICS does not provide forward recovery support for BDAM files,
you can use the autojournal records to provide your own facility.
JREQ=(WU,WN) is the equivalent of the CSD file definition parameters
JNLUPDATE(YES) combined with JNLADD(BEFORE), providing the necessary
images for forward recovery to a journal specified by JID=nn.
For information about defining BDAM file resource definitions, see the CICS
Resource Definition Guide.
The CSD data set
The CICS system definition (CSD) VSAM data set is unique in that it is a CICS
system data set that is managed by CICS file control. For this reason the CSD can't
be defined in the CSD, and is defined instead by system initialization parameters.
The recovery options equivalent to RECOVERY, FWDRECOVLOG, and
BACKUPTYPE are CSDRECOV, CSDFRLOG, and CSDBKUP respectively. See the
CICS System Definition Guide for information about defining the CSD.
File recovery attribute consistency checking (non-RLS)
For data sets accessed in non-RLS mode, ensure you have consistent recovery
attributes between files that refer to the same base data set cluster or its paths.
The first file open for the base data set determines the base data set recovery
attributes, and these are stored in the base cluster block (BCB). If, on a subsequent
file open request, CICS detects an inconsistency between the file definition
recovery attributes and those stored in the BCB, the open request fails.
See “Inquiring on recovery attributes” on page 128 for information about finding
the recovery attributes for files and data sets.
Overriding open failures at the XFCNREC global user exit
CICS provides a global user exit point, XFCNREC, to enable you to continue
processing regardless of any inconsistencies in the backout setting for files
associated with the same data set.
Chapter 12. Defining recoverability for CICS-managed resources 129