Linux Hint published a tutorial about enabling Btrfs filesystem compression.
How to Enable Btrfs Filesystem Compression
The Btrfs filesystem supports filesystem-level data compression. When you access the files stored in your Btrfs filesystem, those files' data will be automatically decompressed. This feature of the filesystem will save you a lot of disk space and will save you a lot of time. In this article, how to enable the Btrfs filesystem-level compression on a Btrfs filesystem is explained.