Changes to consistency group time

If you periodically issue XQUERY commands to the system, the consistency group time increases as long as the primary volumes continue to have update activity.

If update activity ceases for all volumes in the XRC session, the consistency group time does not change for uncoupled sessions. For coupled sessions, the consistency group time increases. In both cases, an XQUERY report displays an IDLE time that indicates how long application updates have been idle.

The consistency group time reported with XQUERY, XDELPAIR, XSUSPEND, XRECOVER, XEND, and XADVANCE messages is dependent on the status of the XRC volume pair at the time the message is issued. For active XRC volume pairs, the consistency group time reported is the consistency group time for the entire XRC session. For suspended XRC volume pairs, the consistency group time is the time that the volume pair was last consistent with the XRC session.

XRC may suspend a volume pair because of an error, or because you have suspended the volume with an XSUSPEND VOLUME or XSUSPEND TIMEOUT command. XRC reports a consistency group time for the volume pair that reflects the last consistency group that XRC secured on the secondary volume.

Other volume pairs in the XRC session continue to have update activity, and their consistency group time continues to advance. At any given moment, the latest timestamp indicates the last consistency group that XRC has successfully secured on the secondary volumes.

An error can occur while XRC attempts to write records in a consistency group to a secondary volume. XRC may successfully write some of the records in this consistency group before the error occurs. In this case, the consistency group time for that volume pair correlates to the last consistency group that XRC successfully wrote to that secondary volume. If XRC has written all of the records in the consistency group to secondary volumes, then the reported consistency group time reflects the latest timestamp of all the records in the consistency group.

Note:

XRC does not assign a consistency group time to a volume in the pending state. The volume has not achieved any consistent state until it is in duplex state. The volume pair is not consistent until XRC has copied all primary volume tracks with their updates to the secondary volume.
If none of the volume pairs have been updated since the session was started, XRC reports "NO_TIME_AVAILABLE" for the consistency group time of the volume pair, the session, or both.
When the CONTIME parmlib parameters are used with the ANTRQST API to retrieve the consistency time for a session in a coupled master session, the consistency time is the same for all sessions in the coupled master session.
Consistency group time is not advanced when L+ volumes are in a session and no I/O activity is seen by XRC for these volumes.