APAR status
Closed as program error.
Error description
When running an instance of the dltmqm program simultaneously for the same Queue Manager on a pair of HA appliances, the program hangs indefinitely. The issue also manifests as inconsistent status when multiple HA commands are performed concurrently. In this case, HA QMgrs were removed from HA group and HA group was deleted. HA group was recreated and three QMgrs were added to the HA group around the same time. However, one of the QMgrs failed to be added to the HA pair. On MQ Appliance 1 (mqa1): mqa(mqcli)# sethagrp -i QM1 Creating high availability configuration on appliance 'mqa1'. AMQ6577E: The command failed because the queue manager already exists on the other appliance in the HA Group. mqa(mqcli)# status QM1 QM(QM1) Status(Ended unexpectedly) Queue manager file system: 92291MB used, 295.3GB allocated [31%] mqa(mqcli)# sethagrp -e Qm1 Removing high availability configuration on this appliance. Removing high availability configuration on appliance 'mqapp2'. AMQ6589W: Failed to remove high availability configuration on appliance 'mqa2'. The user should issue command 'dltmqm' on remote appliance 'mqa2' when it becomes available. The sethagrp command partially succeeded. On MQ Appliance 2 (mqa2): Status command shows the QMgr running elsewhere although the Qmgr is not running on any of the appliances. mqa(mqcli)# status QM1 QM(QM1) Status(Running elsewhere) HA role: UNKNOWN HA status: UNKNOWN HA control: Enabled HA preferred location: None
Local fix
N/A
Problem summary
**************************************************************** USERS AFFECTED: Users of HA on the MQ Appliance at version 9.1.0.2 Platforms affected: MultiPlatform **************************************************************** PROBLEM DESCRIPTION: Due to a programming error, changes made in MQ 9.1.0.2 regarding locking for HA were incomplete. In the scenario where this issue is encountered, the locking mechanism was intended to ensure that the dltmqm command was only run on one appliance at a time. Due to the defective locking logic, the command executed on both appliances concurrently, causing the commands to hang. This issue was introduced by the changes for IT26873, included in the MQ 9.1.0.2 Appliance firmware.
Problem conclusion
The code has been updated so that the HA locking function works correctly. --------------------------------------------------------------- The fix is targeted for delivery in the following PTFs: Version Maintenance Level v9.1 CD 9.1.4 v9.1 LTS 9.1.0.3 The latest available maintenance can be obtained from 'WebSphere MQ Recommended Fixes' http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006037 If the maintenance level is not yet available information on its planned availability can be found in 'WebSphere MQ Planned Maintenance Release Dates' http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006309 ---------------------------------------------------------------
Temporary fix
Comments
APAR Information
APAR number
IT29525
Reported component name
IBM MQ BASE MP
Reported component ID
5724H7271
Reported release
910
Status
CLOSED PER
PE
NoPE
HIPER
YesHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2019-06-24
Closed date
2019-09-30
Last modified date
2019-09-30
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
Fix information
Fixed component name
IBM MQ APPL M20
Fixed component ID
5725Z0900
Applicable component levels
[{"Business Unit":{"code":"BU053","label":"Cloud & Data Platform"},"Product":{"code":"SS5K6E","label":"IBM MQ Appliance"},"Component":"","ARM Category":[],"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"910","Edition":"","Line of Business":{"code":"LOB36","label":"IBM Automation"}}]
Document Information
Modified date:
30 September 2019