what is best?

[mhuff]

I have a customer that is looking at running three MySQL servers with
a total of 78 databases. The initial design as described by the
customer is all three servers will be masters with replication running
between all three.

I am thinking that it might be better to have four MySQL servers on
line, with one master and three slaves, and syncing the master to the
slaves, with the slaves being the servers that are "hit", thus leaving
the master to handle keeping the database(s) upto date.

which would run faster and less errors? As further fyi, the servers
are hosting websites, accept new sign ups, etc, all of which goes into
the databases....this is pretty much all i know at the moment....

Thanks

[pervasync]

Four servers are faster than three servers (of course!). Also it's a
more robust configuration to have a dedicated master.

The pervasync model is a central server synchronizing with multiple
local servers. You could allow read-write on both central server and
local servers. In that sense they are all "masters". Still, you could
call the local servers slaves.

For synchronization/replication, the central server does more
processing than local servers. So it makes sense to let the local
servers deal with user interactions and make central server dedicated
to synchronization.