January 21st, 2014, 12:48 PM
Master to Master Configuration
I'm working on a plan to add a redundant web server and have been pondering how to keep a copy of my SQL databases live on another server.
I've been researching a Master to Master setup and have a few questions:
1) due to budgetary constraints we run the free version of MySQL 5.5. Is this type of configuration possible using this version?
2) if you've used it before, how reliable is it?
January 22nd, 2014, 01:09 PM
1. Yes it is, you are just using the normal replication feature in MySQL which is always available.
2. Well that's the question.
The replication in itself is pretty reliable as long as you don't run out of disk, at which point the binary log can be corrupt and you can loose some of the latest transactions.
BUT the big issue with Master-Master is that if something goes wrong and you get out of sync and have writes to both databases you have big mess to solve.
I prefer a simple Master-Slave setup where all writes are against the master and then switch Master manually.
The failover time is a bit longer but straightening out an out of sync situation is just not fun.