HP NonStop RDF, Management Manual

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Synchronizing Selected Database Portions Online
There are a number of reasons why you might want to synchronize only selected portions of
your database. For example:
• If you have a large database, it might be easier to break the total number of volumes into
subsets, and then synchronize one subset at a time.
• If a file or table has become corrupt, you might want to synchronize just that one file.
• If an individual partition of a file or table has become corrupt, you might want to synchronize
just that one partition.
Overview
To synchronize selected portions of your database, you follow the same steps as those for
synchronizing an entire database.
Example #1 – Staged Synchronization of an Entire Database
Suppose you are synchronizing your entire database by synchronizing selected portions first.
Suppose your database is on ten volumes and you want to synchronize two volumes at a time.
You would start by synchronizing your first two volumes, following the guidelines for
synchronizing an entire database.
When this operation has completed and the RDF updaters are fully caught up, you stop the
NonStop RDF product. You then delete your current RDF configuration and initialize a new
RDF subsystem, using the SYNCHDBTIME option. For the timestamp to be used with the
SYNCHDBTIME attribute, you specify a timestamp following the guidelines for the INITTIME
option.
When you create your new RDF configuration, include the first two volumes you have just
synchronized and include two new volumes. Regarding the first two volumes that are already
synchronized, you do not need to obtain new copies (see
Step 4 ) of the files and tables and load
copies of the files and tables on those volumes because they are already synchronized. For the
two new volumes, you need to synchronize these following the steps for an entire database
synchronization.
When these two new volumes have been synchronized, you follow the same procedure discussed
above, and adding two new volumes to your new RDF configuration file.
Example #2 – Synchronization of an Individual Volume
Suppose you just need either to synchronize a new volume to an existing RDF configuration, or
you need to re-synchronize an existing volume in your configuration. You would first stop your
current RDF subsystem. You then delete your current RDF control subvolume and initialize a
new RDF subsystem, using the SYNCHDBTIME option. For the timestamp to be used with the
SYNCHDBTIME attribute, you specify a timestamp following the guidelines for the INITTIME
option.
When you create your new RDF configuration:
• If you are synchronizing a new volume, add it to your new configuration.
• If you are resynchronizing an existing volume, then just use your existing RDF configuration.
You then follow the guideline for an entire database synchronization operation, except that you
only need to obtain new copies ( see
Step 4 ) of the files and tables on one volume.
Example #3 – Synchronization of an Individual File or Partition on a Volume
Suppose you just need to re-synchronize a single file or partition on an existing volume in your
RDF configuration. You would first stop your current RDF subsystem. You then delete your
current RDF configuration and initialize a new RDF subsystem, using the SYNCHDBTIME
176 Online Database Synchronization