Use the XCOUPLE TSO command to add XRC sessions to, or delete XRC
sessions from, a master session. You can also use this command to
manage the status of the master session. Specifically:
- The XCOUPLE(ADD) command couples the specified XRC session into
a master session, which is then used to coordinate the consistency
time and data recovery of multiple XRC sessions. When two or more
XRC sessions are coupled, the journal and consistency times of the
sessions are maintained such that the entire group of sessions can
always be processed by the XRECOVER or XADVANCE commands to a consistent
point in time. The XCOUPLE(ADD) command is not allowed for sessions
where you specified SESSIONTYPE(MIGRATE) on the XSTART command.
Note: Starting a cluster session in the LPAR that runs XRC,
the XCOUPLE(ADD) command couples the XRC session to the specified
master session through the cluster session. To couple the XRC session
directly to the master session without using a cluster session, disable
the cluster session before you issue the XCOUPLE(ADD) command. If
a cluster session is currently active in the LPAR and you restart
the XRC session, the system recouples an XRC suspended session to
the master session.
- The XCOUPLE(DELETE) command uncouples the specified active XRC
session from the master session. In a coupled environment, when the
last volume is deleted, the system will automatically perform the
XCOUPLE DELETE command to remove the session from the master session.
- The XCOUPLE(PURGE) command is issued to an inactive coupled session.
If the master session is active, this command clears information about
the coupled XRC session from the master data set.
- The
XCOUPLE(RELEASE) command removes the HOLD status of the master session.
Use the RELEASE option only if you no longer need to protect the recoverable
state of the coupled XRC sessions in the master session and are ready
to resume normal remote copy operations.
Note: If you issue the XSTART(
session_id)
command to an XRC session using SESSIONTYPE(MIGRATE), you cannot issue
the XCOUPLE command to couple the session to a master session. If
the XRC session has been migrated and you want to couple it, follow
these steps:
- Issue the XEND or XSUSPEND
command to the session.
- Restart the session by using SESSIONTYPE(XRC).
- Issue the XCOUPLE command to the XRC session
If you restart a coupled session and specify SESSIONTYPE(MIGRATE),
the session type is changed to XRC. To restart a coupled session using
MIGRATE, you must first issue the XCOUPLE PURGE command to uncouple
the session.
Note: - If RACF® facility class
protection is being used for XRC, the XCOUPLE command should be added
to the resource profile by using the procedure documented for existing
XRC commands. The XCOUPLE command must also be defined as an authorized
TSO command.
- The maximum number of coupled sessions that are supported by this
release of CXRC is 14.
If you issue an XSTART command to restart a previously coupled
session, and the automatic XCOUPLE ADD processing fails, subsequent
XADDPAIR commands also fail with a return code indicating that the
XCOUPLE processing is incomplete. To resolve this condition and to
permit XADDPAIR commands to complete, you must either:
- Correct the condition that caused the XCOUPLE ADD command to fail
and reissue the XCOUPLE ADD command to the XRC session that encountered
the problem.
- Issue the XCOUPLE DELETE command to uncouple the XRC session.
For additional information about coupled XRC sessions, refer to Managing coupled XRC operations.