Whither your rollback plan?
MySQL 5.6 upgrades are in full swing these days and knowing how to safely upgrade from MySQL 5.5 to 5.6 is important. When upgrading a replication environment, it’s important that you can build a migration plan that safely allows for your upgrade with minimal risk — rollback is often a very important component to this.
For many people this means upgrading slaves first and then the master. The strategy of an older master replicating to a newer slave is well known and has been supported in MySQL replication for a very long time. To be specific: you can have a MySQL 5.6 slave of a 5.5 master and this should work fine until you upgrade your master and/or promote one of the slaves to be the master.
However, there are those of us who like to live on the edge and do …
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