Mnesia Traffic

Sean Hinde <>
Thu Oct 25 02:44:36 CEST 2001


> Hello,
> I know in previous releases of erlang that if I have a group 
> of nodes all
> running mnesia and replicating that they each talk to every 
> other node on
> the network. This is a concern of the project manager that is 
> responsable
> for giving erlang a yes or a no. He is worried about network traffic.

In the quiet state when there are no updates to replicated tables the only
traffic between mnesia nodes is the normal periodic 'ping' every 45 seconds
or so. I'd be very surprised if this was even measurable in terms of LAN
usage.

If you have lots of replicated tables and are doing lots of updates then the
traffic will be pretty much proportional to the volume of updates.

> Erlang seems to be the perfect choice for this project otherwise. Does
> anyone know of a way around this all talk to all others 
> behavior?

You also have the option to set up erlang nodes with their own standalone
mnesia instances which will not talk to each other at all - simply create a
schema on the local node only: mnesia:create_schema([node()]).

We run quite a number of Erlang nodes in our office environment and have not
come across any problems.

I hope this helps

Rgds,
Sean



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