Abstract

We take the ability to create files and organize them into directories for granted. However, the hard drive certainly doesn’t know what a file or directory is. It’s a job of the file system to bridge the gap between the user and the “spinning rust”, the solid-state drive or even the magnetic tape device.

In this talk, I’ll start by looking at how popular file systems such as NTFS and ext4 work. Then, I’ll introduce the Copy-on-Write concept and show how BTRFS (B-tree file system) employs it to provide a range of new features. The most interesting aspects will be covered in more detail. During the presentation, the trade-off between space usage and performance of file systems will appear.

Finally, I’ll present a working example of BTRFS and some of its distinct features and end the talk by looking at other CoW file systems.