# Function not implemented error only inside docker container (ZFS)

**URL:** <https://forums.docker.com/t/function-not-implemented-error-only-inside-docker-container-zfs/657>\
**Category:** General\
**Created:** [January 19, 2015, 7:32pm UTC](https://forums.docker.com/t/function-not-implemented-error-only-inside-docker-container-zfs/657 "2015-01-19T19:32:38Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![cldfzn](https://avatars.discourse-cdn.com/v4/letter/c/bb73d2/32.png) [@cldfzn](https://forums.docker.com/u/cldfzn)\
**Post date:** [January 19, 2015, 7:32pm UTC](https://forums.docker.com/t/function-not-implemented-error-only-inside-docker-container-zfs/657/1 "2015-01-19T19:32:38Z")

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When running certain applications inside a docker container, such as deluge, I get “Function not implemented:” errors. The /var directory is mounted on a ZFS volume, other than that I do nothing special. If I use the same image on my vm running the same version of ubuntu (14.04.1) and docker (1.4.1) everything will function as expected. Is there an incompatibility with a /var partition mounted on a ZFS volume?

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**Author:** ![svendowideit](https://sea3.discourse-cdn.com/docker/user_avatar/forums.docker.com/svendowideit/32/119_2.png) [@svendowideit](https://forums.docker.com/u/svendowideit)\
**Post date:** [January 27, 2015, 6:30am UTC](https://forums.docker.com/t/function-not-implemented-error-only-inside-docker-container-zfs/657/2 "2015-01-27T06:30:46Z")

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yes. `zfs` is not yet supported, and Docker uses specific features of a subset of filesystem drivers - `aufs`, `btrfs`, `devicemapper` and `overlayfs` to function.