I'm considering adding another server to my one-server setup application with 600GB MySQL DB. The db and the apache are both running from the same server. In order to avoid backup downtime and improve performance, I'm considering to use the additional server as a replication of the db hoping that the write will happen to the master and all the reads will happen from the slave, make it work in parallel.
Is this suitable for an application with many writes? (70%) I assume the write are more effective when done in bulks to the slave. Can I control this? How more effective are they? Is there an easy option to do 'down-time' on one of the servers (e.g. backup) and return to the same system afterwards?