getting rid of the subvol helped and I could delete the share. thanks
I like the idea of having something more high level than just a docker gui, but this also means somebody has to create the necessary files and make the needed adoptions and updates to your approach. which more or less every other NAS system tries to solve as well. the outcome is having outdated docker images running, nobody can easily change or update.
having a system in place which allows to run standard docker images “as well” would make it much easier for users to get the needed features on rockstor. there are already a lot management tools out there, why not integrate one of them as the community “unstable” approach and Rock-ons could still exist as validated and stable solutions for rockstor.
Most people I know choose their NAS in the home environment based on the available plugins.
about unraid vs rockstor 
well I start a discussion about it