Fixes are available
7.0.0.15: WebSphere Application Server V7.0 Fix Pack 15 for AIX
7.0.0.15: Java SDK 1.6 SR9 Cumulative Fix for WebSphere Application Server
7.0.0.15: WebSphere Application Server V7.0 Fix Pack 15 for HP-UX
7.0.0.15: WebSphere Application Server V7.0 Fix Pack 15 for IBM i
7.0.0.15: WebSphere Application Server V7.0 Fix Pack 15 for Linux
7.0.0.15: WebSphere Application Server V7.0 Fix Pack 15 for Solaris
7.0.0.15: WebSphere Application Server V7.0 Fix Pack 15 for Windows
7.0.0.17: WebSphere Application Server V7.0 Fix Pack 17
7.0.0.17: Java SDK 1.6 SR9 FP1 Cumulative Fix for WebSphere Application Server
7.0.0.19: WebSphere Application Server V7.0 Fix Pack 19
7.0.0.21: WebSphere Application Server V7.0 Fix Pack 21
7.0.0.23: WebSphere Application Server V7.0 Fix Pack 23
7.0.0.25: WebSphere Application Server V7.0 Fix Pack 25
7.0.0.27: WebSphere Application Server V7.0 Fix Pack 27
7.0.0.29: WebSphere Application Server V7.0 Fix Pack 29
7.0.0.31: WebSphere Application Server V7.0 Fix Pack 31
7.0.0.27: Java SDK 1.6 SR13 FP2 Cumulative Fix for WebSphere Application Server
7.0.0.33: WebSphere Application Server V7.0 Fix Pack 33
7.0.0.35: WebSphere Application Server V7.0 Fix Pack 35
7.0.0.37: WebSphere Application Server V7.0 Fix Pack 37
7.0.0.39: WebSphere Application Server V7.0 Fix Pack 39
7.0.0.41: WebSphere Application Server V7.0 Fix Pack 41
7.0.0.43: WebSphere Application Server V7.0 Fix Pack 43
7.0.0.45: WebSphere Application Server V7.0 Fix Pack 45
7.0.0.19: Java SDK 1.6 SR9 FP2 Cumulative Fix for WebSphere Application Server
7.0.0.21: Java SDK 1.6 SR9 FP2 Cumulative Fix for WebSphere
7.0.0.23: Java SDK 1.6 SR10 FP1 Cumulative Fix for WebSphere
7.0.0.25: Java SDK 1.6 SR11 Cumulative Fix for WebSphere Application Server
7.0.0.27: Java SDK 1.6 SR12 Cumulative Fix for WebSphere Application Server
7.0.0.29: Java SDK 1.6 SR13 FP2 Cumulative Fix for WebSphere Application Server
7.0.0.45: Java SDK 1.6 SR16 FP60 Cumulative Fix for WebSphere Application Server
7.0.0.31: Java SDK 1.6 SR15 Cumulative Fix for WebSphere Application Server
7.0.0.35: Java SDK 1.6 SR16 FP1 Cumulative Fix for WebSphere Application Server
7.0.0.37: Java SDK 1.6 SR16 FP3 Cumulative Fix for WebSphere Application Server
7.0.0.39: Java SDK 1.6 SR16 FP7 Cumulative Fix for WebSphere Application Server
7.0.0.41: Java SDK 1.6 SR16 FP20 Cumulative Fix for WebSphere Application Server
7.0.0.43: Java SDK 1.6 SR16 FP41 Cumulative Fix for WebSphere Application Server
APAR status
Closed as program error.
Error description
The WeightnceedProportional Algorithm for Proxy creates a routing imbalance.
Local fix
Problem summary
**************************************************************** * USERS AFFECTED: Users of IBM WebSphere Application * * Server V7.0 Proxy Server with multiple * * applications installed to the cluster * * members. * **************************************************************** * PROBLEM DESCRIPTION: Workload management (WLM) Feedback * * Mechanism fails to reset weights * * properly * **************************************************************** * RECOMMENDATION: * **************************************************************** There is code within the WLM algorithms which, by default, will attempt to slightly modify the internally held weight distribution of the cluster members in order to provide better overall throughput. Members with a larger backlog of requests will see less load in the short term versus the members with a smaller backlog of requests. When using a WebSphere Application Server Proxy server and routing requests concurrently to multiple applications installed on the same cluster members, and primarily when the clusters only contain two members, it is possible for the feedback mechanism to get into a bad state and route all the requests for one application to only one cluster member for extended periods of time (anywhere from multiple minutes to multiple hours). Although it would be possible for this problem to occur with more than two members in the cluster, it would be extremely unlikely.
Problem conclusion
Evaluation of the code indicated that the problem with the feedback mechanism in this particular Proxy Server scenario required a solution which would not necessarily be ideal for other routing scenarios. The solution was to create a custom property to force certain behavior out of the feedback mechanism, which would prevent the code from getting into a state of sending requests to only one member for extended periods of time. In order to enable and use the custom property, you must take the following steps: In the administrative console click on "System Administration" on the left side, click on "Cell" underneath that, then click on "Custom Properties" in the middle frame. You'll want to create the following custom property: IBM_CLUSTER_FORCE_FEEDBACK with a value of true. Save that change and sync the config with the nodes, then shut everything down (dmgr NA and servers) and start it up again. If you have WLM trace enabled, you should see this in the trace logs: [3/23/06 15:17:59:828 CST] 0000000a ProcessRuntim > loadCustomProperties Entry [3/23/06 15:17:59:828 CST] 0000000a ProcessRuntim 1 Loaded custom property IBM_CLUSTER_FORCE_FEEDBACK true The fix for this APAR is currently targeted for inclusion in fix pack 7.0.0.15. Please refer to the Recommended Updates page for delivery information: http://www.ibm.com/support/docview.wss?rs=180&uid=swg27004980
Temporary fix
Comments
APAR Information
APAR number
PM13232
Reported component name
WEBSPHERE APP S
Reported component ID
5724J0800
Reported release
700
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt
Submitted date
2010-04-27
Closed date
2010-10-21
Last modified date
2010-10-21
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
WEBSPHERE APP S
Fixed component ID
5724J0800
Applicable component levels
R700 PSY
UP
Document Information
Modified date:
24 October 2021