RDF System Management Manual

Entering RDFCOM Commands
HP NonStop RDF System Management Manual—524388-003
8-45
Command Overview
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If you plan to include the TIMESTAMP option in the INITIALIZE RDF command,
make sure that the primary system database is backed up after the TMF shutdown
so that the backup database can be restored at this point in the audit trail.
Consider the following example:
a. TMF and RDF subsystems are running.
b. TMF subsystem is stopped, and RDF subsystem subsequently stops.
c. TMF subsystem is started and application processing resumed.
d. TMF subsystem is stopped.
If you initialize RDF at the shutdown point at Step d, you should restore on the
backup system a copy of the primary system database taken at Step d. The
databases would not be synchronized if the database at Step b was restored to the
backup system.
If you initialize RDF to the timestamp corresponding to Step b, you should restore
on the backup system a copy of the primary system database taken at Step b.
•
Initialize RDF at the most recent TMF shutdown point. If you initialize RDF at an
earlier shutdown point, RDF operations will start at that point but will shut down
when the next TMF shutdown point is reached. In this case, you must restart RDF
quickly so that operations on the backup system do not fall behind those on the
primary system. If you choose to initialize RDF at a TMF shutdown point that is not
the most recent, watch the RDF event messages for the RDF shutdown message
and then restart RDF immediately.
•
If you include the TIMESTAMP option in the INITIALIZE RDF command, use the
following guidelines to determine when you must restore the backup database:
•
If you are going to start RDF with UPDATE ON, restore the database to the
backup system before you start RDF.
•
If you are going to start RDF with UPDATE OFF, you do not have to restore the
database. However, if the need for an RDF takeover arises, you must then
restore the database on the backup system before you issue the TAKEOVER
command.
•
If you include the TIMESTAMP, INITTIME, or SYNCHDBTIME options in the
INITIALIZE RDF command, it is suggested that all MAT files are present from the
current file to the file containing the TMF shutdown record or the commit/abort
record with a timestamp less than the specified timestamp. If RDFCOM tries to
open a nonexistent file, RDFCOM can trigger restoration of the missing audit trail
files from tape or disk based on your response to a prompt message. Therefore,
not every file in the MAT must be present, from the initial file to the current file. For
example, if the current file is AA000010 and the shutdown record is in AA000009,
only files AA000009 and AA000010 need be present.
•
In any event, if you plan to enable updating on the backup system as part of the
new configuration, ensure that the primary and backup databases are logically