RDF/IMP and IMPX System Management Manual (RDF 1.3+)

Introducing RDF
Compaq NonStop™ RDF/IMP and IMPX System Management Manual—522204-001
1-7
User Interfaces
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Economical processing
RDF conserves resources at both sites.
On the primary system RDF uses just one process (the extractor) per audit trail to
read and transmit audit information to the backup system. The extractor process
automatically filters out any audit information not relevant to the backup database.
On the backup system RDF stores and applies all audit information without using
any primary system resources.
RDF helps balance the load between the primary and backup systems. For example,
to reduce the application load on the primary system, you can perform database
queries on the backup system; RDF does not, however, guarantee database
consistency while changes are being processed for a transaction.
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Access to Consistent Backup Databases
A parameter in the STOP UPDATE command allows users to stop updating at a
specified time stamp, thereby quiescing the backup database in a logically consistent
state with regard to transaction boundaries.
User Interfaces
To use RDF, you run two online utilities: RDFCOM and RDFSCAN. Both are
interactive command interpreters through which you begin a session and enter requests
to the subsystem.
RDFCOM for Subsystem Management and Operations
To manage, operate, and control RDF, use the RDFCOM utility. You can issue
commands to:
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Configure RDF
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Control RDF operation
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Obtain status information about RDF regarding database activity on the primary
system and processing on the backup system
Tasks and examples using RDFCOM commands appear throughout the manual.
Reference information for all commands appears in Section 8, Entering RDFCOM
Commands.
Scanning the EMS Event Log
RDF writes messages to the EMS event log when any of the following occurs:
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RDF is initialized
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RDF is started or stopped
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Updating is started or stopped