On Fri, Aug 21, 2009 at 12:19:01PM +0200, Johan Duflost wrote: > Hello Willy, > > Thank you for your answer. > I will check the stats. > Is this "resonance problem" specific to haproxy?
No not at all, it's specific to the round-robin algorithm instead, which may be implemented in many LBs. The most common way to observe this is when you have two identical servers, an LB in round-robin mode, and a first page with an even number of objects. You try to log in on the servers through the LB and notice you're always logging on to the same server. You can hit reload as many times as you want, once your browser has emitted all requests the round-robin pointer goes back to the first server. This is very annoying when doing benchmarks, because it tends to create unwanted stickiness which makes you think that things might work when they may not. Once the load starts and requests flow in parallel, the effect totally disappears, of course. Willy
