PM12112: CHANGE HOW PLUG-IN FINDS ANOTHER SERVER IF THE AFFINITY SERVER WAS ALREADY MARKED DOWN WHEN THE REQUEST ARRIVES.

Fixes are available

APAR status

Closed as program error.

Error description

In the Failover section of Information Center page "Web server
plug-ins", it has the following description of plug-in failover
behavior:
If a request connection exceeds the time limit specified on the
ConnectTimeout property in the plugin-cfg.xml file, or a 5xx
error is returned from the application server, the Web server
plug-in marks the server as down, and attempts to connect to the
next application server in the list of primary servers that is
specified for the PrimaryServers property in the plugin-cfg.xml
file. If the Web server plug-in successfully connects to another
application server, all requests that were pending for the down
application server are sent to this other application server.
All other new and affinity requests are sent to other servers,
based on whether round robin or random is the setting for the
Load balancing option Web server plug-in request routing
property.
http://publib.boulder.ibm.com/infocenter/wasinfo/v7r0/index.jsp?
topic=/com.ibm.websphere.nd.doc/info/ae/ae/cwsv_plugins.html

Suppose an affinity request arrives at plug-in after the
affinity server had been marked down. Currently, plug-in will
look for the next up application server in the primary server
list; and route the affinity request to it. This behavior is not
the same as described in the Information Center.

Local fix

Problem summary

****************************************************************
* USERS AFFECTED:  IBM WebSphere Application Server web server *
*                  plugin users                                *
****************************************************************
* PROBLEM DESCRIPTION: Failed Affinity connections are not     *
*                      distributed uniformly                   *
****************************************************************
* RECOMMENDATION:                                              *
****************************************************************
When an affinity server is offline, the pending connections
will be directed to the next server in the primaryserver list
instead of distributed among the available servers. This can
cause an overloading of the "next server" which can lead to a
cascading failure situation.

Problem conclusion

The code has been modified to distribute the requests among the
available servers.

The fix for this APAR is currently targeted for inclusion in
fix packs 6.1.0.33 and 7.0.0.13.  Please refer to the
Recommended Updates page for delivery information:
http://www.ibm.com/support/docview.wss?rs=180&uid=swg27004980

Temporary fix

Set the maxconnections to limit the number of connections
which will be sent to the "next server" to avoid an unloading
situation.

Comments

APAR Information

APAR number
PM12112
Reported component name
WEBS APP SERV N
Reported component ID
5724H8800
Reported release
700
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt
Submitted date
2010-04-13
Closed date
2010-04-27
Last modified date
2010-10-15

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
WEBS APP SERV N
Fixed component ID
5724H8800

Applicable component levels

R61A PSY
UP
R61H PSY
UP
R61I PSY
UP
R61P PSY
UP
R61S PSY
UP
R61W PSY
UP
R61Z PSY
UP
R700 PSY
UP

[{"Business Unit":{"code":"BU053","label":"Cloud & Data Platform"},"Product":{"code":"SSEQTP","label":"WebSphere Application Server"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"7.0","Line of Business":{"code":"LOB45","label":"Automation"}}]

Document Information

Modified date:
24 October 2021

Tips

PM12112: CHANGE HOW PLUG-IN FINDS ANOTHER SERVER IF THE AFFINITY SERVER WAS ALREADY MARKED DOWN WHEN THE REQUEST ARRIVES.

Fixes are available

Subscribe

APAR status

Closed as program error.

Error description

Local fix

Problem summary

Problem conclusion

Temporary fix

Comments

APAR Information

APAR number

Reported component name

Reported component ID

Reported release

Status

PE

HIPER

Special Attention

Submitted date

Closed date

Last modified date

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

Fixed component ID

Applicable component levels

R61A PSY

R61H PSY

R61I PSY

R61P PSY

R61S PSY

R61W PSY

R61Z PSY

R700 PSY

Document Information

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