Having switched over to a Galera database clustering setup for some of my applications recently, I needed to be able to monitor the health of the database cluster and its nodes. My environment uses Opsview for monitoring, which is basically a nice wrapper around Nagios for configuration and reporting, so you can use regular Nagios scripts. While looking for an existing Nagios script for Galera, I only found scripts that did not monitor the vital variables of Galera and didn’t fit my needs. So I decided to … Read more
For a very long time, fixing MySQL slaves was a tedious task. Slaves died, replication fails, tables would get out of sync and you’d have to import all the (consistant) data from the master database. Depending on the importance of the slave, this could mean downtime for your master while exporting.
MySQLdump is usually the application one uses to execute this task, locking the tables while exporting. For me, having a database readonly, is downtime. However you look at it, if your website is not 100% useable, it is experiencing downtime.