WebSphere 6.0.2 ND : Cluster member Weight Setting for failover server

[Deepak Dew]

HI,

Here is what I am trying to do and so far I am unable to reach the desired config.

I want to deploy an application in a cluster having two members. Now, I want the first member to be the primary server and the second one to be the backup server/failover server. It means that no request would be sent to the back-server by Plugin unless and until the primary server is down/not-responding.

Also, I dont want to assign the back-server/second server as backup server which can be done over the admin console.

I want to have this config just using the weights only. I basically tried weight of 0 and 1, 0 and 2 but so far it is not working the way I want.

Any inputs asap is greatly appreciated.

Thanks

DD

[Cameron Wallace McKenzie]

I've seen alot of people try to do this type of thing with WebSphere, but never with any true success. Requests get sent to that 'backup' server regardless of how the weights are set.

The weights can control which server the majority of requests will go to, but it will never, from what I have seen, cut a server off completely. The plugin is pretty liberal with regards to when it consideres a server 'down.' Just a slow repsonse from one cluster member will cause WebSphere to spray requests to another server. This is good fo clients, but it stinks for us when we are trying to control the environment.

To truly implement a configuration like this, clients have implemented a switch in front of the cluster, that will spray requests to the second cluster member only when, according to pre-defined rules, the first server is down. But this is a pretty complex solution.

Cheers!

-Cameron McKenzie

[Deepak Dew]

Thanks Cameron

Well, using a switch is out of question here.

When is your book for WebSphere 6 Admin Cert coming out ?
I am eagerly waiting for this. I would be going to WebSphere Tech Conference in Nov-first week and I would be taking the exam there.

I am hoping it comes out within two weeks

Regards

Deepak

[kri shan]

To truly implement a configuration like this, clients have implemented a switch in front of the cluster, that will spray requests to the second

Here switch is the hard-ware Load Balancer ?

[Cameron Wallace McKenzie]

Yes, for the most part.

There are software tools that can make this happen. You can bend some of the WebSphere Edge components to make this happen, and they are software components, but Cisco and Nortel make pretty bulletproof switches that you'd want to use.

When it comes to failover, you don't want a software load balancer running on a Linux or Windows 'throw away box' to be your weakest link in the chain.

Cheers!

-Cameron McKenzie