The CICS® VR
recovery control data set (RCDS) contains essential information for recovering
your VSAM spheres.
The RCDS contains information on the following:
- CICS VR
ISPF dialog interface default values
- MVS™ log
streams
- MVS log
stream copies
- Registered logical backups
- Change accumulation data sets
- CICS VR
VSAM batch logging
- Shadows
This information is stored in three identical linear VSAM data sets. Three
data sets are used to reduce the possibility of data loss. CICS VR regularly
checks to make sure the three data sets are consistent.
The information in the RCDS is updated under the following conditions:
- Through the CICS VR
ISPF dialog
- By using the log of logs scan, with CICS TS
- By using log stream copy, with CICS TS
- Automatically by CICS VR, with change accumulation
- Automatically by CICS VR, with VSAM batch logging
- Automatically by doing a shadow forward recovery
- Automatically when the CICS VR server address space is active
- Automatically when CICS VR is notified of a logical backup
created for a VSAM data set
- Automatically when CICS VR is notified of a VSAM backout failure,
and recovery or reorganization is requested.
You can reduce the likelihood of your RCDS becoming full by
deregistering old information from the RCDS. You can set up automatic deregistration
for your log streams (log stream copies or the log-tail), registered backups,
and change accumulation data sets using the CICS VR panel interface. In addition, you
can instantly deregister the following using the CICS VR dialog interface:
- Log streams
- SAM copies of a log
- Log of logs
- Registered logical backups
Deregistration is triggered by running scan or automatically by the CICS VR
server address space. Once deregistered, CICS VR automatically reuses the freed
space in the RCDS; you never need to manually recover free space. For more
information on automatic deregistration, see Understanding CICS VR automatic deregistration.
The RCDS must be allocated to a recover job for batch REDO
after images unless the recover being run also specifies the REMOTE keyword.
Note: CICS VR
issues an ENQ for each of the RCDSs with QNAME DWWCON,RNAME datasetname,
and with scope SYSTEMS.