What is the “RECLAIMABLE” space displayed in docker system df?

Question

One can use the command docker system df (mirror) (introduced in Docker 1.13.0) to see docker disk usage, e.g.:

username@server:~$ docker system df
TYPE                 


        

Answer 1

It's worth mentioning in addition to Kerat's answer, the command you may be looking for to free up space listed as RECLAIMABLE is docker system prune -a --volumes. Volumes will not be pruned by default if you don't include the --volumes flag.