Specifying the state data set

The state data set defines and contains the status of the XRC session and of associated volumes pairs that XRC is currently managing. The state data set is updated whenever an XADDPAIR, XDELPAIR, XSET, XSUSPEND, XRECOVER, or XEND command is issued, or whenever a volume state changes.

XRC uses a state data set name in one of the following forms:

SYS1.XCOPY.session_id.STATE  or  hlq.XCOPY.session_id.STATE

Rule: The XRC session ID can be up to eight characters long and must be the same name that you will specify with the session_id parameter of the XSTART command.

Example: The following is an example of a state data set name:

 SYS1.XCOPY.DALLAS.STATE

Guidelines: The following are guidelines for the state data set:

Allocate the state data set on disk as an SMS-managed partitioned data set extended (PDSE) data set with the following attributes:
```
DCB=(RECFM=FB,LRECL=4096,BLKSIZE=4096,DSORG=PO),DSNTYPE=LIBRARY
```
Do not allocate the state data set as a generation data set (GDS) PDSE. If you do allocate the state data set as a GDS PDSE, it might cause unpredictable results and interfere with the use of XRC Performance Monitor (XPM) or other utility programs that access the STATE data set.
Allocate ten tracks per storage control session. Try to plan for expected future growth when you initially allocate the state data set, as it may be inconvenient to reallocate it later.
For non-ESS storage controls, allocate one track for each volume pair in the storage control session and try to plan for the expected future growth. For volumes that have a capacity larger than a 3390 Model 3 (3339 cylinders), allocate one additional track for every 3000 additional cylinders. Ensure that the allocation size is sufficient because XRC posts an error if the state data set runs out of space. You cannot add additional storage control sessions or volume pairs if there is insufficient space in the state data set. When there is insufficient space in the state data set, you cannot couple a session to a master session.
Use the following steps to allocate a new, larger data set:
1. Issue XSUSPEND session_id TIMEOUT (hh.mm.ss).
2. Copy all members from the existing state data set to the new, larger data set.
3. Rename the existing state data set to an unused name.
4. Rename the new, larger data set to the pre-existing state data set name.
5. Issue XSTART and resume the XRC operations.
Do not allocate the state data set in the Extended Address Space (EAS) of an Extended Address Volume (EAV) unless you are certain that all SDM LPARs that may potentially require access to the state data set (for example, from all potential active and recovery systems) are at z/OS® V1R12 or higher.

Note: Some environments can benefit from specifying a STORCLAS parameter to ensure that SMS allocates the state data set to the proper SMS-managed volume.

For additional information about the syntax for specific commands, refer to Extended remote copy command descriptions.