#OPENZFS MOUNTPOINT LEGACY HOW TO#
#OPENZFS MOUNTPOINT LEGACY DRIVER#

Suppose you store docker in tank/docker and other files in tank/data. To avoid a slow zfs list, specify the dataset of interest. This explains why you can see 150+ datasets created when only running a dozen containers. You can check the datasets used by one image by running: $ docker image inspect A container is a ZFS clone based on a ZFS Snapshot of the top layer of the image it’s created from. Each child layer is a ZFS clone based on a ZFS snapshot of the layer below it. The base layer of an image is a ZFS filesystem.

#OPENZFS MOUNTPOINT LEGACY DRIVER#

The ZFS storage driver for Docker stores each layer of each image as a separate legacy dataset.Įven just a handful of images can result in a huge number of layers, each layer corresponding to a legacy ZFS dataset. Adding what I eventually found, since this question is one of the top search results. I had the same question but couldn't find a satisfactory answer. # and 150 more of the last two with different hashes Zfs list example: NAME USED AVAIL REFER MOUNTPOINT $ docker images -filter 'dangling=true' -q -no-trunc Proof that docker sees no more dangling counts $ docker ps -qa -no-trunc -filter 'status=exited' Listing zfs volumes now takes ~10 seconds in stead of <1. The excessive use of zfs volumes by docker messes up my zfs list command, both visually and performance-wise.

#OPENZFS MOUNTPOINT LEGACY HOW TO#

If all containers use only the last image layer after pruning the rest, shouldn't docker only use 15 image layers and 15 running containers, totalling 30 volumes? $ sudo zfs list | grep legacy | wc -lĬan I find out if they are in use by a container/image? Is there a command that traverses all pool/var/ datasets in ZFS and figures out to what docker container/image they belong? Either a lot of them can be removed, or I don't understand how to figure out (beyond just trusting docker system prune) they cannot. The rest are (because they are cleaned up).

However, I'm only running about 15 containers, and after running docker system prune -a, the history or every container shows that only the last image layer is still available. $ docker info | grep -e Storage -e Dataset They are all in the form of: pool/var/ 202K 6,18T 818M legacy They started appearing when I started using Docker on this machine: $ sudo zfs list | grep legacy | wc -l There is a huge list of legacy volumes in my Debian zfs pool. I'm wondering if a lot of them are so orphaned that not even docker knows about them anymore, so they don't get cleaned up. This seems like an awful lot of legacy datasets. The storage driver docker users is ZFS ġ6 containers (both running and stopped).

Openzfs mountpoint legacy