@phillxnet Yeah, I think your right I removed some snapshots. Can you tell me why are all these Docker snapshots saved? I removed quite a bit of snapshots and only the “Headphones” rock-on was affected. Resulting in not starting. The other rock-ons were okay. It seems to me it’s just a waste of space…
@MvL OK, that was it then. Good to get to the bottom of it.
It’s down to how docker stores it’s images when using a btrfs backend. Since docker images are composed of layers built on top of one another the docker system can use the btrfs snapshots mechanism (or OverlayFS) to store and share these image snapshots between a number of docker containers. It’s not a waste of space but an efficient use of it.
Given @suman 's response in the later I suspect that there is some improvements to be made, ie I think of late docker has added some ‘clean up’ features that we should be able to enable in the background in time, ie:
docker system df
docker system prune
And a more recently forum thread:
I though we had a current issue open on this but can’t find it so I have created one in the docs repo as a start:
@phillxnet thanks for the extended explanation! Much, much appreciated. It gave me a better understanding. Learned something!
Tried the “docker system prune” command and it deleted 3 volumes.
[root@rockstor containers]# docker system prune
WARNING! This will remove:
- all stopped containers
- all volumes not used by at least one container
- all networks not used by at least one container
- all dangling images
Are you sure you want to continue? [y/N] y
Total reclaimed space: 0 B
the reclaimed space was 0 bytes…, but it looks a bit cleaner.