[erlang-questions] large Erlang clusters

Matt Williamson <>
Sun Aug 17 05:00:50 CEST 2008


If you check out net_ticktime in the kernel_app docs, (you can set it with
net_kernel:set_net_ticktime/1,2), you'll see:

"Once every TickTime/4 second, all connected nodes are ticked (if anything
else has been written to a node) and if nothing has been received from
another node within the last four (4) tick times that node is considered to
be down..."

The default ticktime is 60s, meaning a ping every 15 seconds.

On Sat, Aug 16, 2008 at 5:24 PM, Serge Aleynikov <> wrote:

> I suppose that the problem with the max number of sockets is solved by
> tweaking session limits (ulimit) and using kernel poll (+K true).
>
> As I understand, in a 600 node cluster every node will maintain
> connections to the rest 599 nodes, and send periodic pings.  So, that
> pinging overhead would be something in the order of 10 events per second
>  per node in this configuration.  While the number doesn't seem
> intimidating I wonder if that overhead becomes noticeable in large
> network configurations and if there are any other guidelines that help
> architect such large network clusters to keep background load minimal.
>
> Serge
>
> Viktor Sovietov wrote:
> > Hi Serge
> >
> > As far as I know you're only limited with the maximum number of sockets
> > which are available on your system and with number of atoms which can be
> > used as node names.
> > We tested 600 nodes cluster, but I honestly can't recall if there were
> any
> > patches to BEAM to increase mentioned parameters.
> >
> > Sincerely,
> >
> > --Viktor
> >
> >
> > Serge Aleynikov-2 wrote:
> >> Does any one have experience running somewhere between 200 and 400 nodes
> >> in production?  I recall that Erlang distributed layer had a limit of
> >> 256 nodes.  Is it still the case?
> >>
> >> I suppose that partitioning the cluster in several global_groups should
> >> limit the network load and the number of open file descriptors on each
> >> node would be reduced.
> >>
> >> Are there any other concerns one should be aware of when working with
> >> such large clusters.
> >>
> >> Serge
> >> _______________________________________________
> >> erlang-questions mailing list
> >> 
> >> http://www.erlang.org/mailman/listinfo/erlang-questions
> >>
> >>
> >
>
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