A Quick Question About Btrfs Snapshots

**Diogenes** · 23-Apr-2021, 11:54

When you remove a file from a snapshotted folder, does snapshots still take up full space, that this file used to take up (until snapshots where this file was present are deleted)?

I was compiling a custom kernel, and it generated a 20 GB of files in /usr/src. I didn't need those files anymore, so I deleted them, but it didn't free up any space. However, when I deleted snapshots, around this amount of space was freed up. This is why I am asking.

**hcvv** · 23-Apr-2021, 11:56

Are you meaning Btrfs snapshots? Remind that "snapshot" is a rather general term used in many areas in computing.

**Diogenes** · 23-Apr-2021, 11:57

Originally Posted by hcvv

Are you meaning Btrfs snapshots? Remind that "snapshot" is a rather general term used in many areas in computing.

Yes, I mean btrfs snapshots.

**hcvv** · 23-Apr-2021, 12:43

Originally Posted by Diogenes

Yes, I mean btrfs snapshots.

I changed the subject for you. I assume that avoids confusion with e.g. Tumbleweed Snapshots.

**arvidjaar** · 23-Apr-2021, 13:06

Originally Posted by Diogenes

When you remove a file from a snapshotted folder, does snapshots still take up full space, that this file used to take up (until snapshots where this file was present are deleted)?

Yes. That is the whole reason of snapshot - to preserve the content of file system at the point in time snapshot was taken.

**Diogenes** · 23-Apr-2021, 13:30

Originally Posted by arvidjaar

Yes. That is the whole reason of snapshot - to preserve the content of file system at the point in time snapshot was taken.

OK, thank you! I though that in snapshots previous states might be compressed or somehow optimized, so that they don't take up full space that deleted files used to take up.