A SVC dump is a core dump initiated by the operating system
generally when a programming exception occurs. SVC dump processing
stores data in dump data sets that you pre-allocate, or that the system
allocates automatically as needed.
Alternatively, you can initiate an SVC dump through the MVS™ console, to gather diagnostic data for a 'hang' condition,
for example. SVC dumps that you initiate this way are called console
dumps.
One example of an abend that could occur is the EC3 abend. WebSphere® Application Server for z/OS® requests an SVC dump when a controller terminates a servant
(region) with an EC3 abend when timeout conditions occur.
- Your installation can set parmlib options that determine what
to dump, eliminate duplicate dumps, and so on. WebSphere Application Server for z/OS provides a dump parmlib sample
in
SBBOJCL(BBODMCCB)
.
- The standard SDATA expected in a SVC dump:
SDATA=(ALLNUC,CSA,GRSQ,LPA,LSQA,PSA,RGN,SQA,SUM,SWA,TRT),end
- If you cannot find an SVC dump for a specific abend, your installation
might be using Dump analysis and elimination (DAE) to suppress the
dump. If this is the case, you can change DAE to let the dump be taken
or set a SLIP on the specific abend for a particular job name if the
timeout is consistently happening. For further information, see:
- When you initiate a console dump:
- When you want an SVC dump of a servant region, also request a
dump of the servant's controller region.
- Unless you suspect a particular servant region as the source
of a problem, dump the controller region and all of its servant regions.
- If syslog contains a message indicating that the maxspace limit
was reached for this dump, the SVC dump might be a partial one that
might not contain the data you need to diagnose the timeout. This
limit means that the data set used for SVC dump is not large enough,
and you have to change the size to capture a complete dump.
Note: If you are running WebSphere Application Server
for z/OS with 64-bit support, and you specify RGN
(region) in the SDATA parameter set, you will need to allocate a much
larger space limit for the SVC dump.
- To view CEEDUMP contents within the SVC dump, use the IPCS verbexit
LEDATA, with the CEEDUMP or NTHREADS options, to format and analyze Language Environment® control
blocks. For additional information, see z/OS Language Environment Debugging Guide, GA22-756 for instructions for using IPCS
to format and analyze CEEDUMP contents.
See
z/OS MVS Diagnosis: Tools and Service
Aids, GA22-7589 for additional information about SVC dumps.