IBM SC34-7012-01 File recovery attribute consistency checking non-RLS, Bdam files, CSD data set

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