You can use PostgreSQL together with ZFS and with lz4 compression enabled and maybe gzip will improve performance even more. http://www.citusdata.com/blog/64-zfs-compression
Btrfs also supports compression.
This solution doesn't look production solid for linux server.
I am not sure about lz4, but gzip in my cassandra experience is significantly reducing performance, Db needs spend too much CPU on compression. Snappy works just fine.
