cgit.osmocom.org was down / ezjail disk quota managed by zfs

Just now I only got long waits and then "502 Bad Gateway" on git.osmocom.org ... the cgit ezjail hit its root partition limit. I had to re-figure out what I did last time, tried to find ezjail-admin options until finally I ended up back in zfs and started remembering... I increased the zfs quota for the cgit jail from 10G to 15G. Now it's working again. For the record, resizing an ezjail goes like # zfs list # zfs get quota tank/jails/cgit # zfs set quota=15G tank/jails/cgit (so next time I can find it in my mail archive, and I guess it should go in a wiki somewhere. On osmocom.org?) Last time it was the jenkins jail hitting disc limits. Then I said "We should probably set a refquota so that the live file system's quota is somewhat independent from the quota used for snapshots." I see the jenkins jail now has a 40G refquota, but the others seem not to. How does it work, set a huge quota to allow space for snapshots, and limit the fs itself by a refquota? ~N