HP NonStop RDF J-series RVUs Management Manual page 141

NOTE: If you do not use the ! option and if the primary system is down, then RDFCOM will
need to wait for the Expand level-4 timer to expire. This timer is usually set to 4 or 5 minutes,
and this means that the actual takeover processing does not commence until after the timer
expires. Compared to all the other non-RDF tasks that need to be completed before you can
resume application processing on your backup system, this short delay may not even be noticed.
If the communication lines are down or the monitor and extractor have failed when you issue
the TAKEOVER command, RDF executes the command on the backup system:
• If RDFCOM finds that the primary system is down or that the monitor and extractor do not
exist, then, depending on whether you included the ! option or not, RDFCOM prompts you
to confirm that you want the Takeover operation to proceed.
– If you did not include the ! option, then RDFCOM reports several informational messages
and then asks the following prompt: "Are you sure you want to TAKEOVER?"
You respond with "yes" or "no". If you respond "no", the operation immediately
terminates.
– If you did include the ! option, then you are not prompted and the operation proceeds.
• If RDF is running with updating off, RDFCOM stops the receiver and purger processes, and
then it starts a local RDF monitor process on the backup system in takeover mode. The
monitor then starts the receiver, purger, and all updater processes. (The name of this monitor
on the backup system is generated by the system.)
• If RDF had been stopped, RDFCOM starts the monitor in TAKEOVER mode. The monitor
then starts the receiver, purger, and all updater processes. (The name of this monitor is
generated by the system.)
If a monitor process was started on the backup system, the monitor stops after the other RDF
processes have all shut down.
The following example shows how to use the TAKEOVER command when RDF is running with
updating enabled. The command sequence in the example causes the backup system \TORONTO
to take over processing from the primary system \SANFRAN.
1. At the TACL prompt on the backup system (\TORONTO), start an RDFCOM session and
specify the control subvolume name:
>RDFCOM SANFRAN
2. At the RDFCOM prompt, issue the TAKEOVER command:
]TAKEOVER
RDF displays the following prompt message:
*** TAKEOVER assumes a disaster on \SANFRAN has occurred.
Are you sure you want to TAKEOVER?
3. To proceed with the takeover operation, enter Y or YES.
To abort the takeover operation, enter N or NO.
After you enter your response, RDFCOM returns its prompt. Once the Takeover operation
is underway, you can use the STATUS RDF command to determine the progress of the
takeover operation. If the takeover operation is still in progress, RDF displays the current
state as "TAKEOVER IN PROGRESS."
When the takeover operation finishes, RDF displays a message such as the following in
response to the STATUS RDF command:
STATUS RDF (\RDF04 -> \RDF06) is NOT running
An RDF TAKEOVER has completed
Safe MAT position is SNO 1, RBA 87876660
MAT position for File Recovery: SNO 1, RBA 87876740
Takeover Operations 141