Specifying the master data set

XRC uses the master data set to keep track of multiple XRC sessions that are coupled to the same master session that is associated with the master data set. The master data set must be accessible from, and cataloged on, all SDM hosts and all recovery hosts.

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

```
SYS1.XCOPY.msession_id.MASTER
```
```
mhlq.XCOPY.msession_id.MASTER
```

Where:

msession_id: Specifies the same name that you issued with the MSESSION parameter of the XCOUPLE ADD command. The name can be up to eight characters long. The name you specify for the msession_id cannot be the same as any session_id.
mhlq: Specifies the name of the master data set high-level qualifier that is specified on the MHLQ parameter of the XCOUPLE ADD command. The mhlq must be one to eight characters, and can be any name acceptable to TSO. “SYS1” is the default value.
You can change the default mhlq to a name that corresponds with the MHLQ that is issued on the XCOUPLE command. When you issue the XSUSPEND, XEND, or XQUERY commands with the MASTER option, use the MHLQ parameter. You can also use the MHLQ parameter on the XRECOVER and XQUERY commands to override the defaults.

The following is an example of a master data set name:

SYS1.XCOPY.DALLAS.MASTER