[Linux-cluster] Slowness above 500 RRDs

[David Teigland]

On Mon, May 21, 2007 at 04:42:11PM +0200, Ferenc Wagner wrote:
> Ferenc Wagner <wferi at niif.hu> writes:
> 
> > I installed the new OpenAIS infrastructure (cluster-2.00.00) on my
> > cluster.  Here are the results of the usual tests: [...]
> >
> > The magic limit of 500 disappeared, and flocks are indeed twice as
> > fast as plocks, something you probably expected.  However, in the
> > first test the old infrastructure was much-much faster, doing an
> > iteration in about 0.2 s, thanks to some caching effect.  This is the
> > kind of performance I'm after.  How can I tune the new infrastructure,
> > like cache sizes in the old?  Or should I look for something else?
> 
> One more thing: the old infrastructure became fast when only one (or
> sometimes two) node kept the shared volume mounted.  Now this effect
> is lost as well, a single node or all three nodes mounting the volume
> shows the same not-so-stellar performance.  Is this expected, or do I
> make a mistake somewhere?

That's expected for plocks, but not flocks.

Dave