Hello Willy,
Ok I can understand this issue but when session stickyness is enabled, all
the objects should be retreived from the same server, isn't it?
So it's probably not our problem.
Thanks.
Johan
----- Original Message -----
From: "Willy Tarreau" <w...@1wt.eu>
To: "Johan Duflost" <mail...@decizium.com>
Cc: "Angelo Höngens" <a.hong...@netmatch.nl>; <haproxy@formilux.org>
Sent: Saturday, August 22, 2009 7:51 AM
Subject: Re: round robin
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
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