I've been hit by the login loop issue. In my case it's a filled boot drive. Earlier today I got a warning email from smartd that my boot drive hit 59°.
Followed the excellent tutorial [How-To] Fix full OS filesystem - GUI login loop and narrowed it down to the /var/lib/docker/overlay2 folder.
Running du -xhd1 | sort -h there shows there are 948 directories, with many up to 700MB in size. Also in Portainer there are dozens of images that can't be deleted, but are marked as unused. These are new within the last 48 hours.
Before finding this thread I went to a number of others about login loops, and this is a common issue.
1. Is there a way to reserve some space for OMV to prevent this from happening?
2. Is it possible to reserve the boot drive for only OMV use?
3. Is it possible to change the docker image storage location? I tried changing it under OMV Extras when I first deployed this system, but it didn't work.
4. Any idea why docker or portainer is freaking out and storing all these unused images?
