Collect troubleshooting data for a shared channels problem in IBM MQ for z/OS

Resolving The Problem

Gather this MustGather data before contacting IBM Support:
Collecting general data for all problems
Collecting troubleshooting data for this problem
Troubleshooting hints and tips
Exchanging data with IBM Support

Go back to: IBM MQ (MustGather) Read First

Collecting general data for all problems

A complete description of the problem, including the following:

• IBM MQ version, release, and maintenance level
• Operating system version, release, and maintenance level
• Related products version, and release levels if applicable

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• z/OS Job logs.
  Because a shared channel can be active on any qmgr in the QSG, the joblogs of all the queue managers and CHINs may be needed.
• Dumps generated at point of failure.

• Logrec (JCL to get software LOGREC report).
• Dumps of the MSTR and CHIN requested at the point of failure with MSTR and CHIN trace active.
• Output from MQ commands, where cpf is the command prefix for the queue manager:
• /cpf DISPLAY CHINIT
  This shows:
• Which listeners are started, and information about them.
• How many dispatchers, adapter subtasks, and SSL subtasks are started, and how many were requested.
• The TCP system name.
• How many channel connections are current, and whether they are active, stopped, or retrying.
• The maximum number of current connections.

• /cpf DISPLAY CHSTATUS(xx) CURRENT to get current status.
• /cpf DISPLAY CHSTATUS(xx) SAVED for saved status.
• /cpf DISPLAY CHANNEL(xx) to obtain channel definition.
• CSQUTIL COPY of SYSTEM.QSG.CHANNEL.SYNCQ. This is where shared channels write their sync queue information. See the Example JCL in the IBM MQ for z/OS System Administration Guide.

• A dump of the ADMIN structure: Shared channels are serialized applications. Serialized information is stored in the QSG Admin structure.
  
  /dump comm=(title)
  /r xx,strlist=(strname=QSGnameStructurename,(listnum=all,

• For outbound channels, a dump of the structure where the shared XMITQ is defined
• SPUFI output of the shared channel status DB2 tables:
  SELECT * FROM CSQ.ADMIN_B_SCST ;
  SELECT * FROM CSQ.ADMIN_B_SSKT ;
• z/OS TCP/IP PKTTRACE.

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• Search the IBM MQ support site for known problems using symptoms like the message number and error codes.
• Gather the documentation and work with the IBM MQ support team to resolve your problem.
• See technotes and APARs relating to shared channels.
• See technotes and APARs related to DVIPA (Dynamic Virtual IP Address) for shared inbound channels.
• Technical Exchange - Troubleshooting Communication in IBM MQ and WebSphere MQ Distributed Queuing Overview and Common Problems on z/OS.
• Performance issues:
• Do DISPLAY CHSTATUS on both ends of the channel and check STATUS, SUBSTATE and INDOUBT.
• Use a monitor or RMF data to confirm that the CHIN or TCP/IP task is not suffering dispatching delays due to WLM settings or CPU constraint.
• Be aware that TCP/IP sockets created by the MQ CHINIT take the default send and receive buffer sizes from the TCP/IP profile. If you are using z/OS 1.11 or 1.12, TCP/IP APAR PM16788 should be applied.
• Review a packet or other network trace to see if TCP retransmissions or window sizing are causing delays.
  

• IBM MQ for z/OS concepts: section Distributed queuing and queue-sharing groups.
• Setting up communication for IBM MQ for z/OS using queue-sharing groups.
• Library and Information center.

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• See Exchanging information with IBM Technical Support for FTP and email instructions using the IBM Enhanced Customer Data Repository (ECuRep).
• Go to the Service Request page to open or update a problem.
  Note: Always update your Service Request (problem record) to indicate that data has been sent.

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