mnesia replication

chandru <>
Wed Aug 31 00:30:02 CEST 2005


Hi,

On 30/08/05, Serge Aleynikov <> wrote:
> Hello,
> 
> Could someone comment on the effect of short network outages ( < 10-15
> s) on mnesia replication and how to prevent the inconsistency
> demonstrated in the example below?   I intentionally did not alter the
> net_ticktime kernel parameter so that it would be greater than the
> duration of the brief network outage.

You can't really prevent this inconsistency if you are using dirty
operations. Have you tried the same test using transactions instead of
dirty operations.

> I suspect that this might require to architect the database such that
> objects with same keys would always get updated at a specific node, yet
> I wonder if it is possible to have a true master-master mnesia
> replicated database with presence of short network outages?
> 
It would be unwise to use mnesia in a master-master scenario. The
problem with a master-master scenario is that you will inevitably lose
data when you have a partitioned network even if you use transactions.
Mnesia works extremely well in a master-slave setup. Why do you want a
master-master setup? Is it something you cannot avoid?

cheers,
Chandru



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