----- Original Message -----
> From: "Regan Yelcich" <reganyelcich@stripped>
> Subject: old master to slave?
> Can someone explain the process I should go through to bring an "old" master
> back online as a "slave" after a successful failover using mysql-master-ha?
The classic wisdom is that you just start from scratch again after a failover; especially
if you failed over because there was a problem on the old master.
That being said, there's a few things that can speed you up.
- If you did a controlled failover, you can note the new master's log positions between
turning the old one off and activating the new one. You can then restart the old master as
a slave on those positions, provided of course that the slave was fully updated with the
last of the old master's logs.
- If you use circular replication (aka master-master), the old master will simply pick up
any changes that happen on the other side. The term "master-master" tends to suggest a few
things that this is not, though, so caveat administrator. Read the docs, and read them
- The wonderful Percona Toolkit (formerly Maatkit) contains, among other things, the
pt-table-checksum and pt-table-sync tools, which can help bring a "broken" replication set
back up to speed. They're very good, but there's a few things they can't do (unique
key-less tables are a bugger, for one), so again, read the docs thoroughly.
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