Btrfs Filesystem

Is an alternative filesystem to the usually default ext4 filesystem in linux. It is a Copy-On-Write system meaning that operations on a file result in that file being copied to a new location and a pointer to that file being updated. That means that it is trivial to create snapshots of the system as the pointers to old files only need to be reverted in the case of corruption.

In some systems snapshots are automatically taken when performing certain actions such as upgrading the system.

Btrfs also supports transparent compression meaning that files are compressed when written to disk, which is more cost in terms of cpu usage but results in far less disk usage. This does not significantly slow down system to any significant degree on modern systems due to cpu power available.

Btrfs also support checksums for files meaning the data corruption can detected during routines scans of the system.

Because the system is COW in fstab the option “noatime” is normally specified, meaning that just reading the file does not result in a new copy which would be costly for large files such as videos, etc.

The filesystem also supports the “autodefrag” option in fstab meaning that the filesystem can defragment itself while in use.

It is a logical volume type filesystem meaning that it support a variety of RAID configurations.