[erlang-questions] Erlang suitability

Gleb Peregud <>
Fri May 18 12:27:51 CEST 2012


On Fri, May 18, 2012 at 11:49 AM, Ovid <> wrote:
> 1. We want ACID compliance. We need to ensure that were all 75 boxes to
> mysteriously crash, we could bring them back up and not worry about data
> integrity.

This is mostly guaranteed by Mnesia, but it is sensitive to start/stop
order. I.e. the last node to stop has to be the first node to start
(in most cases this is not necessary, but it is the case if whole
cluster crashed). Please correct me if I'm wrong.

> 2. Our storage needs are likely to become more complex in the future. The
> daily and total capping amounts will eventually be broken down into a
> variety of different categories, along with synchronization of which
> machines bid on a request and if those individual machines won a request
> (something that we currently cannot do without offline aggregation of this
> data).

Not sure if mnesia supports such "sub clusters". Although it probably
run transactions only over nodes on which a involved table is located,
isn't it?

> When you say "75 machines in a fully connected distributed erlang network is
> a bit much but it should work." could you elaborate on that? It makes me a
> bit nervous to hear, particularly since we have no Erlang knowledge and just
> assumed that it was suited for this. Are we thinking about this the wrong
> way?

Mnesia was tailored for 2-3-4-5 nodes at max, since it was designed to
be a storage for storing configuration and short lived data over pairs
of boxes, where one of the boxes is an failover node.



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