File systems form an intermediate layer between block-oriented hard disks and applications, with a volume manager often used between the file system and the hard disk.

To increase the performance, databases can get around the file system and manage the block themselves.

File system <---------------------------Directories and Files
Volume Manager  <-----------------------Logical Blocks

Modern File systems provides 3 functions

1. Journaling -> Mechanism that guarantees the consistency of the file system even after the system crash.
2. Snapshots and -> Same as instant copies  function of disk subsystems.
3. Dynamic file system expansion ->