RDF System Management Manual

Managing RDF
HP NonStop RDF System Management Manual—524388-003
5-14
Stopping RDF by Stopping TMF
For each shutdown procedure, the RDF receiver and updater processes write their
current context information to the RDF context file before stopping. If you restart but do
not reinitialize RDF, the product retrieves the context information from the context file.
The context information enables the RDF processes to resume processing where they
stopped before the shutdown, unless an audit trail file that RDF needs has been
purged and cannot be restored to disk.
Stopping RDF by Stopping TMF
The reason for stopping RDF by stopping TMF is to ensure that the primary and
backup databases are logically identical when the shutdown is complete (RDF has
applied all changes to the backup database). That will be the case, of course, only if all
the updater processes stopped at the shutdown record (if an updater experiences a
double CPU failure, the databases will not be identical). The disadvantage of this
approach is that all applications on the primary system that use TMF must be stopped
also.
Stopping TMF also automatically unpins all audit trail files that were pinned on behalf
of RDF.
When you issue a TMFCOM STOP TMF command, the following events occur:
1. TMF writes a shutdown record to the MAT. When the master extractor reads the
shutdown record, it notifies the monitor that TMF has stopped.
2. The master extractor stops as soon as the master receiver replies that it has
processed the TMF shutdown record.
3. The RDFNET process (if there is an RDF network) does not wait for any other
process to stop; it merely stops when informed to do so.
4. If updating is enabled, each updater process stops when it reaches the TMF
shutdown record in its image trail.
5. The purger stops after all the updaters have stopped.
6. The receiver(s) stop when the purger has stopped.
7. The monitor stops after all the other RDF processes have stopped.
If you stop TMF and then restart it before RDF can read the shutdown record, RDF
stops when it encounters the shutdown record. If that happens, you need to issue a
START RDF command to restart RDF.
Note. If the extractor process falls way behind TMF because the communications lines to the
backup system have been down and come up again, it can take some time for the extractor to
get to the TMF shutdown record. The extractor stops processing the audit trail files when it
cannot communicate with the receiver and resumes processing when the communications
lines are restored.
Note. TMF does not start RDF, which means that if you start TMF, you must then explicitly
start RDF.