Following the solutions to the question i asked recently about mnesia fragmentation, I still have a number of challenges. Consider the following scenario (The question I am asking is based on what follows below):
You have a data driven enterprise application which should be highly available
within the enterprise. If the internal information source is down for any reason,
the enterprise applications must switch to fetch data from a recovery center
which is offsite (remote).You decide to have the database replicated onto Two Nodes within the enterprise
(refered to as DB side A and DB side B). These two are running on separate
Hardware but linked together with say, a Fast Ethernet or Optical Fibre link.
Logically, you create some kind of tunnel or secure communications between these
two Mnesia DBs. The two (A and B) should have the same replica of data and are
in sync all the time.Now, meanwhile, the recovery center must too, have the same copy of data and in
sync all the time just in case the local data access is cutoff due to an attack
or hardware failure. So the same Database schema must be replicated across the 3
sites (Side A , Side B and recovery center).
Now, within the enterprise, the application middle ware is capable of switching data requests amongst the database sites. If A is down, then without the application realizing it, the request is re-routed to Database B and so on. The middle ware layer can be configured to do load balancing (request multiplexing) or to do be flexible with fail over techniques.
Further Analysis:
At Database/Schema creation time, all involved Nodes must be up and running
Mnesia. To achieve this, you create say: 'db_side_A@domain.com',
'db_side_B@domain.com' and fin