I'd like to prohibit new sessions on one of 2 AppServer cluster-members.
The idea behind is that I'd like to stop one AppServer without killing the s
essions of those users that are currently using that server. (Distributed Se
ssions should not be used).

If one would set the loadweight for the "soon dying" AppServer to 0 (while k
eeping the the others >0 ) in the webserver's plugin, I'd expect to have the
 above described effect. Currently existing sessions should then be continue
d on the soon dying AppServ
er while new sessions are only made and forwarded to the AppServer which sta
ys up - until all old sessions on the doomed server end and it can be stoppe
d.

Could you please confirm or counter this idea ?!
Thanks in advance.

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Hi, it sounds like a good idea, but I am not sure that the requests for the 
particular server that the LoadBalanceWeight has been set to 0 will actually
 go back to that server even with session affinity.  Even if it does, how do
 you know that all the user
s are done their processing?

http://publib.boulder.ibm.com/infoc..._plugincfg.html

Brian

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marco_simon@web.de wrote:
> I'd like to prohibit new sessions on one of 2 AppServer
> cluster-members. The idea behind is that I'd like to stop one
> AppServer without killing the sessions of those users that are
> currently using that server. (Distributed Sessions should not be
> used).
>
> If one would set the loadweight for the "soon dying" AppServer to 0
> (while keeping the the others >0 ) in the webserver's plugin, I'd
> expect to have the above described effect. Currently existing
> sessions should then be continued on the soon dying AppServer while
> new sessions are only made and forwarded to the AppServer which stays
> up - until all old sessions on the doomed server end and it can be
> stopped.
>
> Could you please confirm or counter this idea ?!

Setting it to 0 should prevent any more request going to that server,
including existing sessions which will attempt to migrate to another
server in the cluster. If you have no session persistence, you're going
to see errors.

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This says it all in details: "Maintain continuous availability while
updating WebSphere Application Server enterprise applications"
(http://www.ibm.com/developerworks/w...r />
ckel.html)

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> Setting it to 0 should prevent any more request going
> to that server,
> including existing sessions which will attempt to
> migrate to another
> server in the cluster.

That seems not to be correct.
The load-balancing mechanism has an higher priority on session-affinity than
 on equal-balancing. Whenever an internal routing-counter reaches 0, no furt
her _new_ sessions or not-sticky requests are routed to that appserver anyfu
rther. Existing sessions ar
e still routed to the AppServer where they've been created. This makes it po
ssible that the internal routing-counter of the plugin-module becomes negati
ve.

Source of that information:
http://www-1.ibm.com/support/docvie...uid=swg21219567

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