RDF System Management Manual for J-series and H-series RVUs (RDF 1.10)

When you ADD the extractor attributes, RDFCOM checks to ensure that each configured volume
is a valid volume. If any are not, the ADD command fails with an error for the first volume name
that is either an invalid name or does not correspond to a valid volume.
ALTER RDF Remote Mirror Configuration
You can alter the RDF REMOTE MIRROR configuration attribute to turn ZLT protection on and off
as needed. If entered on the primary system, you must stop RDF, alter the attribute, and then restart
RDF. If the primary system is no longer available and you are preparing to start the RDF takeover
operation, you can alter the attribute on the backup system. The syntax is:
ALTER RDF REMOTE MIRROR [ ON | OFF ]
If you issue the ALTER command on the backup system while the network is down and the primary
system is still up, you must then issue the ALTER command again on the primary system when the
network comes back up; otherwise, the change will not be kept on either the primary or the backup
system.
If one of your remote mirrors fails during normal operations on your primary system, you might
want to turn the RDF REMOTE MIRROR configuration attribute off on the primary system so that if
you need to execute a takeover operation you can complete the takeover as quickly as possible.
Remember, if you have the RDF REMOTE MIRROR configuration attribute turned off at the time of
a takeover, you do not have ZLT protection. When the troublesome mirror comes back up and is
fully revived so that it is current with the local mirror, you then re-enable ZLT on the primary to
reinstate ZLT protection.
ZLT Takeover Operations
CAUTION: At the time of a ZLT takeover, HP strongly recommends that before connecting the
remote mirrors to the standby system, you either disconnect the remote mirrors from the primary
RDF system, or disable the XP disk array Logical Unit (LUN) from the primary system. If the remote
mirror's LUN remains shared and active with both the primary and the standby RDF systems, it
might cause data corruption on the remote mirror disk.
If ZLT is configured and enabled when a TAKEOVER command is issued on the backup system,
the overall takeover operation executes in two phases.
NOTE: Before issuing the TAKEOVER command, you must have connected the remote mirrors to
the standby system. When the remote mirrors are connected to the standby system, the audit records
on the remote mirrors have no relationship to the audit trail on the standby system. The remote
mirrors are not part of the TMF configuration of the standby system.
Phase 1 (ZLT Processing)
RDFCOM stops all RDF processes on the backup system. If the standby and backup systems are
not the same system, RDFCOM copies the RDF configuration file on the backup system to the
standby system. RDFCOM then starts an RDF monitor process on the backup system. That monitor
then starts the extractor(s) on the standby system and the receiver(s), purger, and updater(s) on the
backup system.
Each extractor logs RDF event 901 reporting it is started for ZLT processing, starts a special
audit-fixup process to fix up the last file in the audit trail (see “The Audit-Fixup Process” below),
and sends all remaining audit records to its receiver. When an extractor reaches the end of its
audit trail, it sends a “ZLT finished” indication to its receiver, and logs RDF event 900 reporting it
has completed its ZLT task. When all extractors are finished, they are terminated and deleted.
Upon receiving the “ZLT finished” indication, each receiver logs RDF event 903 reporting it has
completed its ZLT task, and tells its updater to commence normal takeover operations. When all
receivers have finished their ZLT processing, the overall takeover operation proceeds to phase 2.
ZLT Takeover Operations 325