CICS® TS
supports the automatic journaling (autojournaling) of file control data to
a specified general log stream. Parameters specified in the CICS definitions
of VSAM files determine whether or not autojournaling is to be performed,
and the types of operations (add, read, or others) that are recorded.
IBM® recommends
that the log records produced by CICS TS autojournaling must only be used
for audit purposes, for the following reasons:
- When a failure occurs during forward recovery logging, CICS performs
certain actions to prevent loss of data, but these actions are not performed
when a failure occurs during autojournaling. Therefore it cannot be guaranteed
that a VSAM sphere is completely and correctly recovered from log records
produced by CICS TS
autojournaling.
- During forward recovery logging, CICS writes specific log records for the
VSAM spheres that are eligible for backup-while-open (BWO) processing. These
log records are required by CICS VR to perform a proper restore and forward recovery
of VSAM spheres from BWO backups. CICS does not write these BWO-specific
log records during CICS TS autojournaling.
- CICS TS
autojournaling does not contain proper RLS support. This means that log records
produced by CICS TS
autojournaling cannot be guaranteed to correctly recover a VSAM sphere that
was opened and updated using RLS.
Despite the known risks, some users want to use log records produced by CICS TS
autojournaling to forward recover VSAM spheres, because this process has the
following advantages over forward recovery logging:
- It eases the transition from CICS/ESA V4R1 to CICS TS (because you do not need to update
the CICS file
definitions with forward recovery logging information).
- It eliminates some of the overhead that occurs with forward recovery logging.
With the possible limitations noted above, CICS VR can forward recover a VSAM sphere
from log records produced by CICS TS autojournaling. However, note again that IBM recommends
using log records produced by CICS forward recovery logging to recover
VSAM spheres. Also, please note the following restrictions when log records
produced by CICS TS
autojournaling are used for the forward recovery of VSAM spheres:
- CICS VR
change accumulation does not support log records produced by CICS TS autojournaling.
- CICS forward
recovery logging must not be enabled for the VSAM spheres that you
want to forward recover from log records produced by CICS TS autojournaling. This means that
the CICS VR
VSAM batch logger cannot at present be used to log updates made to the same
spheres by batch jobs.
The following sections explain the steps required to enable CICS TS autojournaling
for VSAM spheres and to set up CICS VR to forward recover the spheres
from the autojournal log records.