Major issue with LVS-DR when a server gets overloaded

[Joseph Mack NA3T]

On Tue, 30 Jan 2007, Matthias Saou wrote:

> traffic, the exact same issue as with the ServerIron happened!
> Symptoms :
> - The virtual IP address no longer responds on port 80, it times out
> - The real server having problems gets REALLY overloaded

perhaps you should ask about this on the keepalived mailing 
list. There should be a hysteresis that stops the realserver 
flapping.

> - All other 5 real servers no longer receive any traffic
> - ipvsadm show no new active or inactive connections (counters stay the
> same), only the persistent connections counters decrease slowly (as
> expected since there are no new connections...)

never seen this before. The other realservers should be 
receiving packets just fine unless something else is jammed 
(eg the upstream router is overloaded with icmp unreachable)

> I would like to have tried some kind of "keep the real server disabled
> for n seconds when it's detected as down" in order to keep the check
> from flip-flopping like this, but there is no such setting in
> keepalived AFAICS.

I'm surprised it's not in there. Ask ALexandre about it.

Joe
-- 
Joseph Mack NA3T EME(B,D), FM05lw North Carolina
jmack (at) wm7d (dot) net - azimuthal equidistant map
generator at http://www.wm7d.net/azproj.shtml
Homepage http://www.austintek.com/ It's GNU/Linux!