Hi!
Ok, I get it. The master is listed in the wgDBServer
variable, and
the
slaves in the wgDBServers array of arrays. Upon failure of the
master,
it's a manual process to get writes working again, but reads should
function fine.
Wikimedia database setup is slightly evolved already. We have
multiple sets of databases (enwiki/others), and some slaves work only
with particular datasets (like holbach, our 4GB box has only dewiki).
Additionally we employ application servers in our text external
storage role. So we have our own partitioning already.
Since I already have my wiki on a replicated 4.1
database, it's a
whole
lot less work than building a new MySQL 5.0 cluster from scratch with
that large learning curve.
You can always ask MySQL to assist - they've got consultants who have
lots of experience with mediawiki!!!! ;-)
Domas