MustGather: Collect Trouble Shooting Data for Read First/Fix List for Persistent Sessions for z/OS Communications Server

Resolving The Problem

Table Of Contents

Section 1: General Persistent Sessions Information

• Section 1.1: Recommended Maintenance

Section 2: Multinode Persistent Sessions (MNPS) Specific Information

• Section 2.1: Recommended Maintenance

Section 1: General Persistent Sessions Information

Single node persistent sessions applies to application failures only. If an application program fails or is brought down, VTAM can retain active sessions, allowing the same or another application to reconnect to the sessions, avoiding the need to re-establish the sessions. If an application fails, it can reconnect to the retained sessions when it recovers. Also another application program can take over the sessions.

Multi-node persistent sessions extends the support to allow a VTAM application to move to another VTAM. This move may be after a VTAM, operation system or hardware failure or the move may be a planned activity. The application can be restarted on an alternate VTAM and the application's sessions restored after a VTAM failure. The application can also restart on the same VTAM once VTAM has been restarted.

Persistent session problems have varied external symptoms such as : PSS hangs, ABEND0C4's because of a reference to a freed PST, or invalid data via data tracking in the CV29. If a user is utilizing VTAM's persistent session function, the following maintenance is recommended.

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Section 1.1: Recommended Maintenance

For any z/OS release, apply the highest level of ISTOCCPC available for the release.

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Section 2: Multinode Persistent Sessions (MNPS) Specific Information

For MNPS problems, the following documentation needs to be obtained:
I) VIT,MODE=EXT,OPTIONS=(CFS,HPR,PIU,MSG,SMS,NRM,SSCP,PSS)
II) Dump which includes VTAM and application address space, MNPS dataspace and all MNPS coupling facility structures being used.

NOTE: The coupling facility structures are included in the dump by specifying:
STRLIST=(STRNAME=IST.......,ACC=NOLIMIT,(LNUM=ALL,EDATA=SER,
ADJ=CAP))

To find the correct dataspace,enter D A,VTAM440 (or whatever your VTAM job name is) right after the recovery open. The recovery dataspace is the one at the top of the list.

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Section 2.1: Recommended Maintenance

For any z/OS release, apply the highest level of ISTOCCMO available for the release.

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