CSS11501 direct all requests to one server?

[smc]

Hi,

We have a CSS 11501 with 2 webservers behind it. The people from serveradmin want one webserver to be used for all requests, and only use the second one when the first one gets too busy (let's say > 80 %)

So in a very busy scenario, both webservers would be used

I've looked into Primary sorry server but believe that's only to be used when the first webserver dies, so this does not apply.

I also thought about using different weights for the services, but even when you give webserver 1 a weight of 10, and webserver 2 a weight of 1, there will still be requests forwarded - albeit very few - to webserver 2, right?

Anyone encountered this before? Any help greatly appreciated.

Regards,

Radboud

[Gilles Dufour · Accepted solution]

firs you have to define what is 80%

The CSS has now knowledge of the capacity of the servers.

I see 2 options to define 80%.

First you know that your box can handle 100 connections.

So you can define 80% to be 80 connections.

You could then configure maxconn to 80.

The primarysorryserver will kick in once maxconns has been reached for all other servers.

Another solution is a script on the server itself that measure the load and update a file with a value ON or OFF.

When reaching 80% of maxload, simple rewrite the file with the vaule off.

On the CSS create a keepalive to read this file and disable the service if the value is off.

When disabled, the primarysorryserver will kick in.

Regards,

Gilles.

[smc]

Gilles,

Sorry I didn't mention, with 80 % I whas thinking about for example when looking at serverload.

In that respect, the CSS does know about capacity of the servers

about your solutions:

1) Max connections: This looks a fine solution to me, I think I'll try this first

2) scripting: This might also work, except that I wouldn't want the CSS to disable the busy service, rather to activate a normally suspended service (in effect have both servers working) Once the load drops below 80 %, (value on server 1 is ON) the second service should be suspended by the CSS.

Thanks a lot Gilles!

grtz Radboud