RDF System Management Manual

Entering RDFCOM Commands
HP NonStop RDF System Management Manual—524388-003
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Command Overview
begins reading from the current image file at the same place that the receiver process
begins writing.
The master image trail identified by the RDFVOLUME parameter in the SET
RECEIVER command is reserved for use by the MAT receiver process. All updaters
must be configured to secondary image trails. Each image trail is stored on a separate
volume on the backup system. To add a secondary image trail, you specify the disk
volume intended for its use through the ADD IMAGETRAIL command. When you
configure your individual updater processes with the SET VOLUME command, you
assign each of these processes to a different image trail, reducing the number of
updaters contending for a specific trail.
Each secondary image trail contains only that audit data required by the associated
updaters. Image files in secondary image trails have the same extent sizes as image
files on the volume specified by RDFVOLUME. Because the extent sizes for
secondary image trails are obtained from the receiver’s configuration record, you do
not specify them through any RDFCOM commands.
With RDF/IMP, IMPX, or ZLT, if your RDF configuration is not particularly small (say, 30
volumes or more) and your performance requirements are not high, you can assign
one image trail per updater process, and you can place that image trail on the
updater’s UPDATEVOLUME. If you have the need for high performance, however,
even on a small system, it might be best to have a dedicated volume for your image
trails.
You cannot add secondary image trails until you have configured the receiver, because
the extent sizes for these trails depend on those specified for the receiver’s master
image files.
Examples
To configure the extractor process named $EXT to run in CPUs 0 and 1 at the default
priority of 165 with the default RTD warning threshold of 60 seconds, enter the
following commands:
]SET EXTRACTOR PROCESS $EXT
]SET EXTRACTOR CPUS 0:1
]ADD EXTRACTOR
Caution. After RDF is configured and running, do not add an updater process unless a STOP
TMF command has shut down RDF; otherwise, you cannot be sure that the data on the newly
added backup system volume is synchronized with the data on the corresponding primary
system volume.