RDF/IMP, IMPX, and ZLT System Management Manual

Managing RDF
HP NonStop RDF/IMP, IMPX, and ZLT System Management Manual—524388-002
5-15
Restarting RDF
An alternative way to stop RDF on the backup system is to enter the following
command through TACL:
>STATUS *, PROG RDF-software-loc.*, STOP
Restarting RDF
If you want to restart RDF and have it resume processing where it stopped at the
previous shutdown, you can only do so if you have not reinitialized RDF subsystem
since the shutdown.
Use the START RDF command to restart RDF. RDF automatically starts with UPDATE
ON unless you explicitly specify UPDATE OFF in the START RDF command.
When RDF restarts, it uses the information in the context files to determine where it
last stopped, and resumes processing from that point.
Carrying Out a Planned Switchover
Many businesses run online transaction processing (OLTP) twenty-four hours a day.
Stopping applications to perform software or hardware upgrades, repairs, or other
maintenance can result in complications and inconvenience for system users. To
minimize such planned outages, you can perform a planned switchover from the
primary system to the backup system to keep applications running while you modify or
repair the primary system.
Standard Configurations for Switchover
In a standard RDF configuration (system \A the primary, system \B the backup), the
steps for performing a planned switchover from \A to \B are:
1. On system \A, stop the business applications that access the primary database.
2. On system \A, issue a STOP TMF command.
TMF stops as soon as all outstanding database transactions are either committed
or aborted. It then writes a shutdown record to the MAT. Subsequently, the RDF
subsystem shuts down when all updater processes on the backup system (\B)
have reached the shutdown record in the image trail file. At this point, the primary
and backup databases are identical.
3. On system \B, note the local system time; you’ll need it later.
4. On system \B, restart the business applications.
Caution. Issuing this command in this situation is only safe, however, if this is the backup
system for a single RDF environment.
Note. If you delete and reconfigure TMF, then you must initialize RDF.