RDF/IMP and IMPX System Management Manual (RDF 1.4+)

Introducing RDF
HP NonStop RDF/IMP and IMPX System Management Manual—524388-001
1-28
Available Types of Replication to Multiple Backup
Systems
Available Types of Replication to Multiple
Backup Systems
The RDF product allows you to replicate database changes from a single primary
system to multiple backup systems. This makes possible simultaneous read-only
access to all of the backup systems, a capability particularly desirable for query-
intensive applications where a central volatile database can be distributed to several
remote systems for local access by queries.
Replication to multiple backup systems is achieved by establishing multiple RDF
configurations, all protecting the database or portions of it on the same primary system.
As an example, you might wish to replicate the same data to different backup systems,
as follows:
RDF Configuration #1
\A ---------> \B
RDF Configuration #2
\A ---------> \C
RDF Configuration #3
\A ---------> \D
Alternatively, you might have one RDF configuration replicate data on a set of volumes
to one backup system and another RDF configuration replicate data on a different set
of volumes to a different backup system, as follows:
RDF Configuration #1, protecting Volumes $DAT1 through $DAT20
\A ---------> \B
RDF Configuration #2, protecting Volumes $DAT21 through
$DAT40
\A ---------> \C
As still another alternative, you might have one RDF configuration replicate data on a
set of volumes to a backup system and a different RDF configuration replicate data on
a different set of volumes to the same backup system as the other RDF configuration,
in this way:
RDF Configuration #1, protecting Volumes $DAT1 through $DAT20
\A ---------> \B
RDF Configuration #2, protecting Volumes $DAT21 through
$DAT40
\A ---------> \B
In the preceding examples, each RDF configuration operates entirely independently of
the other RDF configuration primaried on the same node; that is, each RDF
configuration has its own extractor and monitor process. In this way, line failures
affecting one configuration may not necessarily affect the others (depending on the
configuration).