MySQL architecture ~mha Frequently asked questions

A brief introduction: Today to talk about MHA related issues

Two questions brocade set

1 MHA Architecture If it hangs from the library, does it affect the process?

The default is to cause the process to exit unexpectedly.

Add parameter ignore_fail=1 from library even if hanging off will not affect MHA monitoring process

2 MHA Default detection mechanism

1 its own detection mechanism MHA service periodic detection of the main library, periodic select per second

2 provides additional script detection originating from the specified IP address

3 MHA Switching process

1. Get the Binlog event from the down master.

2, determine the latest (most complete) from the library.

3. Apply different relay log events to other slave libraries, respectively.

4. Apply the Binlog event obtained from the main library (event at the time of failure).

5. Upgrade one from the library to the new main library (this time from the library has been consistent).

4 MHA Switching failure scenarios

1 MHA The default latency tolerance is 0, so there is a delay that can cause the switching time to increase or even fail

2 A problem with the configuration file can also cause a switchover to fail

6. Reassign other libraries from the main library

MySQL architecture ~mha Frequently asked questions