I'm using postgresql and neo4j as backend data stores for my application (More about Polyglot Persistence in http://martinfowler.com/bliki/PolyglotPersistence.html ). Both Neo4j and Postgresql support backup mechanisms.
Neo4j(Online backup) : http://docs.neo4j.org/chunked/stable/operations-backup.html
Postgres(Point In Time Recovery(PITR) backup): http://www.postgresql.org/docs/9.1/static/continuous-archiving.html
The problem here is how to take backups of these two stores such that on recovery you get back a consistent state even at the cost of losing some data. Any ideas/suggestions are welcome.