It seems pretty common to find customers install DRBD for the wrong reasons. There are many pros/cons to compare DRBD to replication, but I've managed to cut down my spiel I give to customers to these two points:
- DRBD's aim (assuming replication mode C) is to provide 100% consistency, and then as much uptime as possible.
- MySQL Replication (with a manager such as MMM) aims to have 100% availability, at the potential loss of some data surrounding a failure.
So if you are installing DRBD with the aim of purely "availability", and are …[Read more...]