RDF System Management Manual

Table Of Contents
Introducing RDF
HP NonStop RDF System Management Manual524388-003
1-10
Features
Master and auxiliary audit trail protection
RDF can protect all tables and files that are being audited by TMF, whether they
are associated with the master audit trail (MAT) or an auxiliary audit trail.
Subvolume and file replication
In addition to volume replication, the RDF/IMP and IMPX products support
replication of selected subvolumes and files.
Economical processing
RDF conserves resources at both sites. The extractor typically uses 1% of the
resources used by the application on the primary and 4% of the Expand resources.
On the backup system the cost of an updater process replicating an update
operation is typically 15-25% of the original cost to do the operation on the primary
system.
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.
Access to Consistent Backup Databases
There are two ways to quiesce the backup database in a logically consistent state
with regard to transaction boundaries: stop TMF on the primary system or use the
TIMESTAMP parameter in a STOP UPDATE command (referred to as a stop-
update-to-time operation). The latter allows you to do so without stopping TMF,
your applications, or the RDF extractor.
Zero Lost Transactions (ZLT)
ZLT is a functional capability that uses mirrored disks to guarantee that no
committed transactions on the primary system will be lost in the event of an RDF
takeover by the backup system.