| Session | Description |
|---|---|
| Active session | An XRC session in which the system data mover is running. Volumes
can be added or deleted.
You can issue the XADVANCE command and the XCOUPLE command with ADD and DELETE parameters to individual active XRC sessions. |
| Coupled session | An active individual XRC session has been added to a master session. |
| Inactive session | A session in which the system data
mover is not active.
You can issue the XADVANCE, XSTART, XRECOVER, and the XCOUPLE commands with the PURGE parameter to individual inactive XRC sessions. |
| Interlocked session | A coupled XRC session in a master
session that has a consistency time before the master journal time
and a journal time equal to or after the master recoverable time.
The master recoverable time is the minimum of the journal times reported by all XRC sessions. This is the latest time to which all sessions could recover their data in the event of a disaster, and still provide coupled consistency. XRC will recover all interlocked sessions such that all secondary volumes across the coupled interlocked sessions will be consistent. Because coupled consistency requires all volumes to be at the same time, no session is allowed to apply data which is after the master recoverable time. |
| Master session | A logical entity that is used to coordinate session commands
and data consistency across multiple XRC sessions. A master session
exists as long as there is an XRC session coupled to the master session.
You can issue the XQUERY, XEND, XSUSPEND, and XCOUPLE RELEASE commands to a master session. |
| Cluster session | A logical entity that manages a group of
coupled sessions within a single logical partition, and represents
this group as a single coupled session in a master session (for example:
single SDM).
XRC commands cannot be issued to an active (enabled) cluster session. |
| Suspended session | You can issue the XADVANCE command, XSTART command, XRECOVER command, and the XCOUPLE command with the PURGE parameter to individual suspended XRC sessions. |
| XRC session | A logical entity that is created for processing XRC commands. |
For additional information about XRC sessions as they apply in a uncoupled environment, refer to XRC session state descriptions.