Re: ClusterIP network slowdown

[Michele Codutti <michele.codutti@uniud.it>]

Hi Edison, you're right, all the host on the same switch can see the
packages directed to the clusterip. But this is not a problem because
these other hosts are not affected by the slowdown. The only affected
nodes are the ones that are using the clusterip.
I cannot modify any configuration of any switch on my network without a
long process for approval i can not try to enable the igmp snooping
without a strong argument. How can igmp snooping relief some load on the
clustered hosts? 
There are any kernel parameters that i can tune to make clusterip behave
better?
I'm sorry for being so pedant but i need some precise technical
information to modify something in my network.

Thanks.

Il giorno mar, 30/11/2010 alle 10.59 -0200, Edison Figueira ha scritto:
> Hi Michele,
> 
> Both cases is because the CLUSTERIP uses broadcast addresses to
> work, in the first case the message is because the packet is sent to
> two machines and one of them always drops in order, to solve this
> just disable debug netfilter.
> 
> The second case is probably because all the packages that are
> being sent to the CLUSTERIP are being copied to all
> ports on your switch, to confirm this do a tcpdump on any workstation.
> 
> The solution to this case is, enable "IGMP snooping" on your switch.
> 
> Att
> 
> Edison Figueira Junior
> 
> 2010/11/30 Michele Codutti <michele.codutti@uniud.it>
> >
> > Hello, in these days i had fun with the ClusterIP target associated to a
> > web server. All is good and bright with the exception of two issues:
> > - the message "CLUSTERIP: no conntrack!"
> > - a general slowdown of the other network services (like ssh) of the two
> > nodes of the cluster.
> > To solve all my problems i've inserted this iptables rule:
> > iptables -I INPUT 1 -m state --state INVALID -j DROP
> > This is a solution that isn't good enough because i manage the apache2
> > and the clustered ip with heartbeat2.
> > Example: if i standby a node (for maintenance) and resume it after a
> > while this can be a problem because heartbeat put the clusterip rule on
> > top of the others so the dropping rule above became the second one and
> > then the workaround had no effect.
> > Why the clusterip had such an heavy impact on the networking? Before the
> > clusterip my cluster was active-standby and i've got no problems at all.
> > Now that the load per node is halved i noticed more load than before.
> > The strangest thing is that (with the top tool) this load seem not exist
> > and the nodes are not loaded at all:
> > load average: 0.50, 0.36, 0.37
> > How can i fix this without the dropping rule above?
> > There is a way to see how the networking is loaded?
> >
> > Thanks in advance.
> >
> > Michele
> >
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