RDF System Management Manual

HP NonStop RDF System Management Manual—524388-003
6-1
6 Maintaining the Databases
A vital task in working with RDF is to keep the backup and primary databases
synchronized with each other. This section, which is intended for database
administrators, begins with a discussion of the synchronized and unsynchronized
database states. It then explains how you can maintain database synchronization by:
•
Backing up changes to the database structure
•
Resynchronizing the primary and backup databases
Understanding Database States
It is important to understand the terms used to describe the different states of a primary
database and its associated backup database. The following illustrations show
synchronized and unsynchronized databases.
In the illustrations, \PRIMARY indicates the primary system and database, and
\BACKUP indicates the backup system and database. Tx indicates the data associated
with a committed transaction. In some illustrations, the extractor and updater process
operations also appear.
Figure 6-1 shows synchronized databases where RDF has just been initialized and the
application on \PRIMARY is going to be started. The databases are synchronized
because they contain the same logical data and no audit has been generated.
Figure 6-1. Synchronized Databases Before Starting RDF
MAT
Image File
Database Database
\PRIMARY \BACKUP
T1
T1
T3
T2
T3
T2