Server Fault is a question and answer site for system and network administrators. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

So I'm currently testing a new DB topology before moving it into a production environment, and I've run into a rather odd problem. The current setup is as follows: 5 server instances. 2 are MySQL DBs in Master/Master . 2 are slaves that point to a virtual IP(VIP), which currently points to one of those masters. The 5th server is load balancing between the slaves using MySQL proxy.

So the idea is to have all reads done on the slaves, and all writes occur on the Master. Everything is working almost fine - anything wrote to the Master that the VIP is pointing to is propagated to the slaves, and the Masters are mirroring each other.

The problem is that when I write to the Master that is NOT currently pointed to by the VIP, it propagates over to the other Master, but that change is not propagated over to the slaves.

I know that this is a convoluted problem/question. If anyone has any ideas I would certainly appreciate a point in the right direction.

share|improve this question
So the fifth server with mysql-proxy is a single point of failure? – symcbean Jun 29 '11 at 12:30
As of right now, that's the next piece I'm going to look at. I figured out the problem btw, log-slave-updates wasn't on – Sam Jun 29 '11 at 16:12
up vote 0 down vote accepted

Yea, the issue was that the log-slave-updates flag was not on. I'm currently investigating proxies for traffic splitting, it seems like haproxy is the way to go. Even though it's not designed for SQL specifically, it's not in alpha like mysql-proxy.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.