PQ74545: PLUGIN MARKS THE ONLY APPSERVER DOWN

 Fixes are available

5.0.2: WebSphere Application Server Version 5.0 Fix Pack 2 (Version 5.0.2)
PQ86603: IBM HTTP Server V2.0.x mod_alias/mod_rewrite conflict with V5.0 plug-in



APAR status
Closed as program error.

Error description
In a plugin trace can be seen this error message:
"ERROR: ws_server: serverSetFailoverStatus: Marking AppServer
down".
Next 60 seconds in a case that RetryInterval of ServerGroup
is not set, all subsequent http requests to appServer fail.
This problem is highly visible with thread based WebServer,
such as iPlanet or IHS/Apache on Windows.
Desired behaviour would be to have a configurable parameter
in plugin config file.
The customer should have a choice to decide, if they want
the plugin to mark the only application server down in
a simple WebSphere environment without server groups & clones,
or to mark down the only AppServer that is up in a cloning
WebSpheer environment.
Please, take into consideration also a technote:
"How to configure a weighted load balancing mechanism for the
WebSphere plugin" that was written by Sharon McCloskey.
Local fix
Set RetryInterval of ServerGroup to some low value, such as
5 or 10 seconds.  It might influence performance (but I am
not sure how much).
Problem summary
****************************************************************
* USERS AFFECTED: WebSphere Application Server plugin users    *
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* PROBLEM DESCRIPTION: Only server in ServerGroup marked down. *
****************************************************************
* RECOMMENDATION:                                              *
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In versions prior to 4.0, the failover code would not
mark down the only server in a server group, as marking
it down didn't really do anything useful:  there's no failover
if there's only one server in the ServerGroup, so marking
the server down will at best make it take a little bit longer
for the plugins to notice when the only application server
comes back up.  This APAR is to extend this behavior of
not marking down the only server in a ServerGroup to WebSphere
versions 4 and above.
Problem conclusion
This APAR pulls the behavior of 4.0 back into line with
the older failover mechanism it was based on.  Keep in
mind that this fix only improves our behavior in cases
where there is only one server in a ServerGroup, and is
not meant as a fix for servers being marked down for
unknown reasons.  For any situation where a server is being
marked down for unknown reasons, work still needs to be
done to work out why the server is being marked down, even
if applying this APAR makes the symptoms less severe -
the kinds of things that cause servers to be marked down
randomly are usually signs of a deeper problem that needs
to be addressed.
Temporary fix Comments
APAR information
APAR number PQ74545
Reported component name WAS BASE 5.0
Reported component ID 5630A3600
Reported release 00W
Status CLOSED PER
PE NoPE
HIPER NoHIPER
Special Attention NoSpecatt
Submitted date 2003-05-23
Closed date 2003-05-23
Last modified date 2003-05-23

APAR is sysrouted FROM one or more of the following:
PQ71608

APAR is sysrouted TO one or more of the following:

Modules/Macros
Plugin          

Publications Referenced

Fix information
Fixed component name WAS BASE 5.0
Fixed component ID 5630A3600

Applicable component levels
R00W PSY    UP


Document Information


Product categories: Software > Application Servers > Distributed Application & Web Servers > WebSphere Application Server > General
Operating system(s):
Software version: 00W
Software edition:
Reference #: PQ74545
IBM Group: Software Group
Modified date: May 23, 2003