Shouldn't ACE 4710 ignore cookie stickiness when the server is down?

g.eleftheriou · ‎02-03-2010

Hello,

I have implemented sticky load balancing with cookies. The problem is that if one of my two servers in the server farm is down (and even if the ace recognizes it as down via a probe) it keeps sending the requests to the server that is down, obviously because it has set a cookie for this server,

Shouldn't the ACE ignore the cookie when the server is down?

Is there a command to ignore cookie stickiness if the server is down? Is there another workaround?

an example of my config is

serverfarm host SF_Ebanking
rserver RS_IAS_1 XXXX
    conn-limit max 4000000 min 4000000
    probe http_probe_ebanking
    inservice
rserver RS_IAS_2 XXXX
    conn-limit max 4000000 min 4000000
    probe http_probe_ebanking
    inservice

sticky http-cookie ACE_COOKIE ebanking_sticky
cookie insert
replicate sticky
serverfarm SF_Ebanking
16 static cookie-value "server01" rserver RS_IAS_1
24 static cookie-value "server02" rserver RS_IAS_2

thanks,

george

Gilles Dufour · ‎02-03-2010

This is not as obvious as you seem to believe.

ACE will not select a server that is down !!!! Even if the cookie points to that server.

What might be happening is that the connection from the browser to the ACE has not been killed, so when client sends a new request it reuses the existing connection and ACE does allow an existing connection to be maintain with a dead server by default.

Try the command 'failaction purge' under the serverfarm.

This should kill the active connections with the dead server and allow a new connection to be open with the other server even if the cookie points to the dead one.

Regards,

Gilles.