Troubleshooting
Problem
The "above bar" (64-bit) storage usage reported by the IBM MQ queue manager suddenly increased.
Symptom
The "above bar" values increased in message:
CSQY220I Queue manager storage usage: local storage: used mmMB, free nnMB: above bar: used aabb, free cc
The System Action in the description of CSQY225E says:
"Processing continues. Storage contraction processing was performed, but the remaining deallocated virtual storage is less than a predetermined safe amount. If storage use continues to increase, the queue manager might terminate abnormally in an unpredictable way."
CSQY220I Queue manager storage usage: local storage: used mmMB, free nnMB: above bar: used aabb, free cc
The values can increase to be larger than the MEMLIMIT value specified in the JCL for the queue manager.
The following messages might also appear:
CSQY224I CSQSCTL Queue Manager is short of local storage above the bar.
CSQY225E CSQSCTL Queue Manager is critically short of local storage above the bar - take action
The System Action in the description of CSQY225E says:
"Processing continues. Storage contraction processing was performed, but the remaining deallocated virtual storage is less than a predetermined safe amount. If storage use continues to increase, the queue manager might terminate abnormally in an unpredictable way."
Cause
OA53037 is for
****************************************************************
* USERS AFFECTED: *
* Installations using Parallel Sysplex that uses lock or *
* serialized list structures at z/OS V2R3 (HBB77B0). *
****************************************************************
* PROBLEM DESCRIPTION: *
* New function is required to relieve constraints affecting *
* the maximum number of connectors to lock or serialized list *
* structures from a single address space. *
****************************************************************
The APAR provides constraint relief for XES (Cross-system Extended Services) lock dataspaces by moving applicable control blocks from dataspaces to above-the-bar 64-bit storage. It relieves constraint on the number of connectors from a given address space.
The PTF has Additional Information saying:
IBM MQ users with a Queue Sharing Group (QSG) use connectors for each CFSTRUCT (Coupling Facility structure).
****************************************************************
* USERS AFFECTED: *
* Installations using Parallel Sysplex that uses lock or *
* serialized list structures at z/OS V2R3 (HBB77B0). *
****************************************************************
* PROBLEM DESCRIPTION: *
* New function is required to relieve constraints affecting *
* the maximum number of connectors to lock or serialized list *
* structures from a single address space. *
****************************************************************
The APAR provides constraint relief for XES (Cross-system Extended Services) lock dataspaces by moving applicable control blocks from dataspaces to above-the-bar 64-bit storage. It relieves constraint on the number of connectors from a given address space.
The PTF has Additional Information saying:
With the change introduced by this PTF, XES allocates 4G of
storage in high virtual per connection to a serialized list
structure or 36G per connection to a lock structure. Prior
to this change, this storage was allocated in dataspaces. After
application of this APAR, based on the way IBM MQ currently
calculates storage usage, CSQY225E and CSQY224I may be issued
indicating 'Queue manager is short of local storage above the
bar'. Because XES specifies MEMLIMIT=NO on the GETSTOR request,
this storage object will not count towards the MEMLIMIT
value so no adjustment to the MEMLIMIT parameter in the MQ JCL
is needed..
IBM MQ users with a Queue Sharing Group (QSG) use connectors for each CFSTRUCT (Coupling Facility structure).
Resolving The Problem
Apply the appropriate IBM MQ fix from this list:
- V8.0.0: PI98759/UI59437
The fix updates how IBM MQ calculates the above-the-bar storage used by IBM MQ so that this MEMLIMIT=NO storage is not counted.
No adjustment to the MEMLIMIT parameter in the IBM MQ JCL is needed because the MEMLIMIT=NO storage used by XES will not count towards the queue manager's MEMLIMIT use.
No adjustment to the MEMLIMIT parameter in the IBM MQ JCL is needed because the MEMLIMIT=NO storage used by XES will not count towards the queue manager's MEMLIMIT use.
[{"Business Unit":{"code":"BU053","label":"Cloud & Data Platform"},"Product":{"code":"SSYHRD","label":"IBM MQ"},"Component":"Storage Constraint (SOS)","Platform":[{"code":"PF035","label":"z\/OS"}],"Version":"9.1;9.0;8.0","Edition":"","Line of Business":{"code":"LOB45","label":"Automation"}},{"Product":{"code":"SWG90","label":"z\/OS"},"Business Unit":{"code":"BU058","label":"IBM Infrastructure w\/TPS"},"Component":"5752SCIXL - CROSS SYSTEM EXTENDED SERVICES (XES)","Platform":[{"code":"PF035","label":"z\/OS"}],"Version":"2.3","Edition":"","Line of Business":{"code":"LOB56","label":"Z HW"}}]
Product Synonym
IBM MQ WebSphere MQ IMQ WMQ
Was this topic helpful?
Document Information
Modified date:
03 September 2021
UID
swg22017139