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In data martedì 31 marzo 2009 16:04:41, Joseph Mack NA3T ha scritto:
> On Tue, 31 Mar 2009, Fabio Coatti wrote:
> > Basically, the scenario is the following: 5 servers (RIP),
> > balanced with ipvs on linux 2.6.23, DR is used. All works
> > just fine, but if for some reasons the real servers
> > freezes and need reboot, ipvs keeps as "alive" all the
> > connections so the balancing is not correctly done.
>
> ipvs has no way of knowing that a machine has been rebooted,
> so this is the expected behaviour. Health checking is all
> external to ipvs. Since in LVS-DR the director doesn't see
> the returning packets, it has to guess when connections
> expire, and you've set a long timeout.
Yes, I know this part, and in fact I don't blame lvs for falling in this
situation; basically It would be useful a quick way to recover (by hand) when
something weird happens and lvs gets confused.
>
> Either
>
> o use the -SH scheduler to direct clients to the same
> database server and return the timeouts to the default
> period.
Hm, interesting, but I fear that this will lead to non-optimal situations when
from the same machine many connections are started.
>
> o use one of the ioctls that Horms wrote to handle crashed
> realservers when ipvs is using persistence. These clear out
> the connection table
This would be the good solution for my issue, indeed. Thanks for the
suggestion, with it I finally found some hints. If I read correctly the
documentation,
/proc/sys/net/ipv4/vs/expire_quiescent_template
and
/proc/sys/net/ipv4/vs/expire_nodest_conn
should help to solve the issue..
I'll try asap.
Thanks.
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