RDF System Management Manual for J-series and H-series RVUs (RDF Update 13)

NOTE: The hardware configuration for use of a remote mirror on the audit trail is not part of the
RDF configuration, nor is it part of any RDF validation. You must have placed the remote mirror in
a location where you can connect it to the standby system at the time of a takeover. If you fail to
do this, the RDF takeover operation fails until you have connected the remote mirror to the standby
system or turned off remote mirroring. See “ALTER RDF Remote Mirror Configuration” (page 334).
Extractor Audit-Trail Configuration
When configuring RDF for ZLT, you must add the complete set of audit trail volumes to which
RDF-protected data volumes are configured. For example, if your RDF configuration only protects
data volumes configured to the Master Audit Trail (MAT), you must specify all audit trail volumes
that are configured in TMF for the MAT (active, overflow, and restore). Because each audit trail
can have up to 16 active, 16 restore, and 16 overflow volumes, an extractor list can contain up
to 48 volume names. Set each volume name:
SET EXTRACTOR VOLUME volume-name
volume-name must be a valid volume name specified in the current TMF configuration on your
primary system. Use a SET statement for each individual volume. You do not need to specify whether
the volume is an active volume, restore volume, or overflow volume; you merely specify the volume
name. The list of volumes you specify is placed in the extractor configuration record.
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.
334 Zero Lost Transactions (ZLT)