Clustering MySQL with InnoDB engine I have a MySQL single server setup with all tables using the InnoDB engine (because I need support for foreign keys). As response times are getting longer, I now believe I need to create a cluster of servers to be able to cope with an ever-growing database load.

Is it possible to create a cluster of MySQL servers using my existing databases which use InnoDB? If not, what are my options?
Moving to Galera would be an option. Then your application has to be aware of 'deadlock detected try restarting transaction' errors. 
Another possibility is to set up a read slave and configure your application to use this slave for read_only queries. If one slave isn't enough you can add more and use them with a loadbalancer of any kind. Examples are maxScale, ha-proxy on application layer or ipvs on transport layer.