This is a Request for Input. Dual MySQL masters with MMM in a
single datacentre are in common use, and other setups like DRBD
and of course VM/SAN based failover solutions are conceptually
straightforward also. Thus, achieving various forms of resilience
within a single data-centre is doable and not costly.
Doing the same across multiple (let’s for simplicity sake limit
it to two) datacentres is another matter. MySQL replication works
well across longer links, and it can use MySQL’s in-built SSL or
tools like stunnel. Of course it needs to be kept an eye on, as
usual, but since it’s asynchronous the latency between the
datacentres is not a big issue (apart from the fact that the
second server gets up-to-date a little bit later).
But as those who have tried will know, having a client
(application server) connection to a MySQL instance in a remote
data-centre is a whole other matter, latency becomes a big issue
and is generally …[Read more]