MySQL DB quad-directional synchronization without master server?

Question

I need to set up 4 MySQL servers. Each of them needs to support both reads and writes, so a master server (that accepts only writes) is out of the question. I need the data between these 4 servers to be synchronized. It does not matter to me if they have a constant connection open between themselves or if they each connect periodically. I looked at the MySQL replication page but did not find it useful for what I need. What is the best way to do this?

Answer 1

It's called multi master replication, there are tools like mmm to help accomplish this.

Though be warn, it can be very lengthy manual process to recover from replication failures, as you'll end up with situation where you're unsure which copy of the data is more up to date.