Re: Replication RO/RW DBs on same server.

[Jonathan Tullett]

Hi,

thank you very much for your reply!

I think it's simpler than you thought.
This is just the kind of response I was hoping for :)

Just set up circular replication (A replicates B, B replicates A) and 
> ensure, at the application level, that
you only write on one machine for each separate database. MySQL handles
circular replication: updates travel round the circle until the reach the
machine which originated them, when they are dropped. If you are handling
the changeover logic yourself, you have very little problem. When the
application detects that the machine it was using has failed, it should
switch to the slave. 
Makes perfect sense.

I was considering having a floating IP for each of the machines, so that 
if one dies, the other takes over the others IP address, thus making 
changes at the application level unnecessary really.

Reconstruction when the failed machine comes back is
more of a problem.
I would imagine that taking a snapshot of the databases and restarting 
replication should solve that one tho?

Using circular replication, I imagine I could have N machines, with each 
machine having its own RW DB, and each machine having N-1 RO dbs? 
Obviously fail over in this instance would be more of a problem to deal 
with, but manageable.

Many thanks for your advice, it has made both myself, and my boss very 
happy.

Jonathan.

--
MySQL General Mailing List
For list archives: http://lists.mysql.com/mysql
To unsubscribe:    http://lists.mysql.com/[EMAIL PROTECTED]