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

Entering RDFCOM Commands
Compaq NonStop™ RDF/IMP and IMPX System Management Manual—522204-001
8-87
Command Overview
RTD Time
The third column (labeled RTD Time) specifies the current RDF time delay (RTD) value
for the extractor process, receiver process, and all updater processes. These values can
help you determine how far behind the application program each process is running.
On the primary system, TMF attaches a timestamp to every commit and abort status
record generated for the application program. The extractor process, in turn, attaches
the most recent TMF commit/abort timestamp to all data modification image records.
The RTD value for each extractor is the difference between the “last modified time” of
the TMF master audit trail (MAT) and the timestamp in the most recent image record
processed by that extractor.
As each receiver processes records, it writes them to a buffer and then moves them from
the buffer as the need arises. Each receiver keeps track of the last audit record it wrote
to disk at the last save point; if the receiver must restart because the primary system goes
down, this save point becomes the receiver’s restart point. The RTD for a receiver is the
difference between the “last modified time” of the TMF MAT and the timestamp that
identifies the associated restart point.
The RTD value reported for each updater process is the difference between the “last
modified time” of the TMF master audit trail (MAT) and the timestamp in the most
recent image record seen by the particular updater.
The RTD value reflects, in the most general sense, the amount of time by which the
backup database is lagging behind the primary database. In the example shown under
“Output Displayed” earlier in this command description, the specified RTD time for the
updater $TU04 is 0 minutes and 10 seconds, meaning that the updater is running
approximately 10 seconds behind the MAT.
On a finely tuned RDF backup node, the RTD for an updater can regularly lag 5 to 50
seconds behind TMF processing. However, this 50-second delay does not mean that 50
seconds are needed to catch up; that operation may only a few seconds.
Pri
The fourth column specifies the priority at which each process is running.
Volume and Seqnce
The fifth and sixth columns together specify a file associated with each process, as
follows:
•
The monitor entry reflects the name of the MAT file to which TMF is writing
($AUDIT.ZTMFAT.AA000056 in this example).
•
Each extractor entry reflects the name of the TMF audit trail file from which it is
reading ($AUDIT.ZTMFAT.AA000056 for the master extractor and
$DATA17.ZTMFAT.BB000004 for the auxiliary extractor in this example).
•
The receiver entries reflect the names of the primary image trail files to which each
receiver is writing ($DATA01.RDF04.AA000044 and $DATA02.RDF04.AA000003
in this example).