That's a filesystem isn't it (not NFS as locks don't work properly on NFS filesystems)? 1. One per user - in home directory. Check. 2. Real database with meta

That's a filesystem isn't it (not NFS as locks don't work properly on NFS filesystems)? 1. One per user - in home directory. Check. 2. Real database with metadata - filesystem. Check. 3. Replication - filesystem (block replication). Check. 4. Redundancy - filesystem (RAID). Check. So technically it already does that without any need for further abstraction. You can use UNIX perms to set it read only for all and read-write for user, then you can share it :) For reference, I've built a HUGE amount of stuff with sqlite3 - you are right it does make the world a better place! We use it for: 1. unit test back end for NHibernate as it's fast and in memory. 2. issue/tickets/wiki (trac) 3. data processing. 4. archival datasets. 5. general swiss army knife when you can't be bothered to do it in SSIS.