The CICSPlex® SM data repository is defined to CICS® as a VSAM file called EYUDREP. As the
data set is accessed via CICS File Control, all the normal CICS methods of
taking backups of VSAM data sets for disaster recovery purposes are available
for use with the data repository.
You may use the following techniques for taking copies of the data repository,
and for restoring the data repository after a data set failure.
- Use HSM, or DSS, or other utilities to take copies while the associated
CMAS is not running, possibly using the Concurrent Copy technique to reduce
the time during which the repository must be unavailable.
- Use HSM or DSS to take copies while the associated CMAS is running using
the Backup While Open technique, and possibly also using the Concurrent Copy
technique, which improves the ease of use of Backup While Open. This requires
a forward recovery log (see Defining a forward recovery log for the data repository).
- Use HSM or DSS to restore the data set after a data set failure.
- Use a Forward Recovery product, such as CICS VSAM Recovery (CICS/VR), to reapply updates
that were made to the data set after the most recent copy was taken. This
requires a forward recovery log.
- Use remote site recovery techniques if you need an up-to-date copy of
the data set at a remote site for disaster recovery purposes. This requires
a forward recovery log.
The CICS Recovery and Restart Guide provides information on all the
terms referred to above. In particular, it provides information about forward
recovery logs, forward recovery, the CICS/VR product, Backup While Open, Concurrent
Copy and its associated hardware prerequisites, taking back ups of data sets,
restoring data sets from backup copies, and remote site recovery.
The data repository is defined in the CMAS as a VSAM file called EYUDREP. CICSPlex SM provides a default definition that defines this file
as not having an associated forward recovery log, and therefore as not being
eligible for forward recovery.
If you use forward recovery,
you require a journal logstream. Defining CICS log streams is described in the CICS System Definition Guide, and setting up a journal logstream is described in the CICS System Definition Guide.
If you wish to use Forward Recovery, Backup While Open, or Remote Site
Recovery, you will need to change the definition of EYUDREP. You will need
to specify the following keywords on the definition of EYUDREP to define it
as having a forward recovery log:
RECOVERY(ALL)
FWDRECOVLOG(nn)
where nn is a number between 1 and 99.
The default definition of EYUDREP also does not define the repository as
being eligible for Backup While Open. To make the repository eligible for
Backup While Open, you should specify the following keywords:
RECOVERY(ALL)
FWDRECOVLOG(nn)
BACKUPTYPE(DYNAMIC)
where nn is a number between 1 and 99.
The RECOVERY, FWDRECOVLOG, and BACKUPTYPE parameters of DEFINE FILE are
described fully in the CICS Resource Definition Guide.
Notes:
- You should not change any keywords on the EYUDREP definition other than
RECOVERY, FWDRECOVLOG and BACKUPTYPE. In addition, you must never set RECOVERY(NONE).
Setting RECOVERY(NONE) would cause repository corruption after transaction
or CMAS failures.
- You should not change the recovery options of the EYUDREPN FILE definition.
This definition is used when CPSM determines that Data Repository file operations
do not require logging. It is normal to receive LSR pool messages
for EYUDREPN during CMAS initialization and you should ignore them. There
should be no DD statement in the CICS JCL for EYUDREPN and EYUDREPN should
not be associated with a data set name.
- If CPSM Data Repository initialization fails (as reported by message EUIXD0105E)
and the cause is due to the EYUDREP data set requiring Batch Backout (for
example CICS issues message DFHFC0921), you must recover the EYUDREP data set
and then delete and redefine the CMAS Local and Global catalogs in order to
reset the CICS backout required status for the data set.
- Requesting Backup While Open
for the CICSPlex SM data repository data set via the IDCAMS DEFINE CLUSTER definition
within the ICF catalog is not supported.
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