I'd like to multi-home a proprietary web-based application for a relatively small user base with modest dataset size. Scalability is not as much of a concern as extremely high availability. The system has extremely basic architecture: PHP running on a single Linux VPS tapping into a standard MySQL server.
I'm thinking to use multiple VPS's in geographically distinct datacenters such that if a user has problems connecting to one server location, they can try another (I have separate ideas on how to semi-automate the failover, and potentially georoute, but that's another issue). PHP application code and other files would be rsynced; however, I haven't yet resolved how to sync the databases... is it reasonable to use MySQL Cluster for this?
If one node goes down, the others must continue working. When a node comes back up, it should automatically get back in sync. Given that there would be WAN-type latency between datacenters, write speed cannot be dependent on intra-cluster connectivity. Data consistency is desirable but not the overriding priority. System simplicity is important--I can't afford to spend the next month figuring out the nuances of the database.
If MySQL Cluster is not appropriate for this, then what are some other alternatives to consider?