On Sat, 3 Sep 2011, Russell Sim <russell.sim@gmail.com> wrote:

On Fri, Sep 02, 2011 at 10:41:30AM +1000, Trent W. Buck wrote:

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Is that what haproxy is for? (I haven't used it myself, but it sounds close.)

i have used haproxy, for http load balancing and my uni was using it for LDAP load balancing, until one of the ldap servers started having problems and haproxy was unable to detect the problems, so for a few months ldap queries worked half of the time. So just be aware that HAProxy might not understand there is a problem if your backends don't behave correctly.

Thanks for the suggestion, haproxy is now working well for me. I'm using it for SpamAssassin and the spamc client seems to recognise errors in the protocol. This combined with a round-robin configuration of haproxy should mean that if one of the spamd servers goes down then I get 1/4 of the incoming mail attempts deferred with a 45x code. This won't stop the system being usable but I will have to improve my monitoring to catch this. -- My Main Blog http://etbe.coker.com.au/ My Documents Blog http://doc.coker.com.au/