Using configuration restart data sets

To use the z/OS® Communications Server configuration restart facility, define configuration restart Virtual Storage Access Method (VSAM) data sets.

Procedure

To set up data sets for the major nodes that you will be using with configuration restart, perform the following steps. See z/OS Communications Server: SNA Network Implementation Guide for a description of the configuration restart support.

Use a DD statement to define a configuration restart VSAM data set for each major node. The ddname must match the ddname on the CONFGDS operand of either the PCCU definition statement for the associated NCP or the VBUILD definition statement for the associated major node. There are no z/OS Communications Server restrictions on this data set name.
This example defines a catalog entry to allocate space for a VSAM data set to contain the configuration restart data:
```
DEFINE
  CLUSTER(NAME(RESTART) -
          VOL(PUBLIC) -
          KEYS(18 0) -
          DATA(NAME(RESTART.DATA) -
          RECORDS(200 20) -
          RECORDSIZE(46 158)) -
  INDEX(NAME(RESTARTI.INDEX) -
          TRACKS(1))
```
Code the INDEX operand on the DEFINE command, or let it default. (See the sample DEFINE command.) The data set must be indexed.
Code KEYS (18 0). A key length of 18 bytes and an offset of 0 bytes are required.
Code RECORDSIZE (46 158). The average record size must be 46 bytes, and the maximum record size must be 158 bytes.
Make sure that the number of records in the file is equal to the number of minor nodes defined in the major node. When you choose the number of records for a switched major node, include each PATH definition statement. Therefore, the primary allocation should be the number of minor nodes in the major node, and the secondary allocation should be about 0.1 times the number of minor nodes.
When you change a major node definition in SYS1.VTAMLST, do not use the WARM start option when activating the new definition for the first time.