MySQL High Availability

Chapter 11. Replication Troubleshooting

The message subject was simply “Fix the Seattle server.” Joel knew such cryptic subject lines came from only one person. A quick scan of the message header confirmed the email was from Mr. Summerson. Joel opened the message and read the contents.

“The Seattle server is acting up again. I think the replication thingy is hosed. Make this your top priority.”

“OK,” Joel muttered to himself. Because the monitoring reports he had produced last week showed no anomalies and he was sure the replication setup was correct the last time he checked, Joel wasn’t sure how to attack the problem. But he knew where to find the answers. “It looks like I need to read that replication troubleshooting chapter after all.”

A familiar head appeared in his doorway. Joel decided to perform a preemptive maneuver by saying, “I’m on it.” This resulted in a nod and a casual salute as his boss continued down the hall.

MySQL replication is usually trouble-free and rarely needs tuning or tweaking once the topology is active and properly configured. However, there are times when things can go wrong. Sometimes an error is manifested, and you have clear evidence with which to start your investigations. Other times the condition or problem is easily understood, but the causes of the more difficult problems that can arise are not so obvious. Fortunately, you can resolve these problems if you follow some simple guidelines and practices for troubleshooting replication.

This chapter presents ...