RDF System Management Manual

Introducing RDF
HP NonStop RDF System Management Manual—524388-003
1-8
Features
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Flexibility in protection
You can run RDF with updating on the backup system either enabled or disabled.
RDF is also very flexible with regard to system interrelationships and to disk usage
requirements on backup systems. Besides the most basic configuration of a single
primary system protected by a single backup system, you can have configurations
such as the following (see Figure 1-2, RDF Topologies):
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Multiple primary systems protected by one backup system.
•
Reciprocal protection between two systems, where each is the backup to the
other (different databases on the two systems).
•
A single primary system whose database changes are replicated to databases
on multiple backup systems. Such an environment makes possible
simultaneous read-only access to all of the backup databases (this is desirable
for query-intensive applications such as telephone directory assistance).
•
Triple contingency—a special instance of the database replication feature
whereby a single primary system is protected by two identical backup systems.
This feature allows your applications to resume, with full RDF protection, within
minutes after the loss of your primary system, provided the two backup
systems are not too far behind.
•
Loopback configuration—where the primary and backup systems are the same
system. This has no value from a disaster protection standpoint, but can be
useful for testing purposes. Data from a set of volumes can be replicated to a
different set of volumes on the same node.
RDF does not require an identical one-to-one volume relationship between
volumes on the primary system and those on the backup system. Backup volume
names do not have to match primary volume names. The subsystem can direct
audit information from more than one audited volume on the primary system to a
single volume on the backup system, provided that no more than one partition of a
file exists on any backup volume. (For information on partitioned files, see the
Guardian User’s Guide.)
•
Application independence
RDF is application-independent; it can protect data for any application that uses
NonStop SQL/MP and NonStop SQL/MX tables and indexes or Enscribe record
manager files audited by TMF.
RDF supports the following audited file types: key-sequenced, entry-sequenced,
and relative (for NonStop SQL/MP or Enscribe) and Enscribe queue files.
Unstructured Enscribe files are not supported.