erlang - What is Mnesia replication strategy? -

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  1. what strategy mnesia use define nodes store replicas of particular table?
  2. can force mnesia use specific number of replicas each table? can number changed dynamically?
  3. are there sources (besides source code) detailed (not overview) description of mnesia internal algorithms?

  1. manual. you're responsible specifying replicated where.
  2. yes, above, manually. can changed dynamically.
  3. i'm afraid (though may wrong) none besides source code. in terms of documenation whole erlang distribution hardly leader in software world.

mnesia not automatically manage number of replicas of given table. responsible specifying each node store table replica (hence number). replica may then:

  • stored in memory,
  • stored on disk,
  • stored both in memory , on disk,
  • not stored on node - in case table accessible data fetched on demand other node(s).

it's possible reconfigure replication strategy when system running, though dynamically (based on node-down event example) have come solution yourself.

the mnesia system events used discover situation when node goes down; given know tables stored on node check number of online replicas based on nodes still online , perform replication if needed.

i'm not aware of application/library manages kind of stuff , seems quite advanced (from point of view, @ least) endeavor make one.

however, riak database manages data distribution among it's nodes transparently user , configurable respect options mentioned. may way go you.


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