I seem to have horribly broken MySQL on our Ubuntu 14.04 LTS server. We recently installed the mysql-proxy package(we've been trying to set up master-master replication, but we've abandoned that for Tungsten), and I suspect that was what did the damage, although removing that package still does not bring the server back to life.
Starting MySQL results in the following output in our logs:
150421 16:44:56 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql 150421 16:44:56 [Note] Plugin 'FEDERATED' is disabled. 150421 16:44:56 [Note] Plugin 'InnoDB' is disabled. 150421 16:44:56 [ERROR] Unknown/unsupported storage engine: InnoDB 150421 16:44:56 [ERROR] Aborting 150421 16:44:56 [Note] /usr/sbin/mysqld: Shutdown complete 150421 16:44:56 mysqld_safe mysqld from pid file /var/run/mysqld/mysqld.pid ended
And yes, I've tried the trick of removing /var/lib/mysql/ib_logfile0 and /var/lib/mysql/ib_logfile1 and restarting. MySQL just complains that these files don't exist, and that we need to re-create them.