I use a USB HDD as NAS drive on my pi4 with OMV5 (installed ~4 month ago). The device is mounted correctly after reboot.
The NAS HDD will be unmounted during runtime when I connect another USB HDD for backups (hot plug-in, both HDDs have additional power supplies).
There is a change from sda1 to sdb1 or sdc1.
The NAS HDD will only be mounted automatically when it appears as sda1 even the label DATA is used in fstab (OMV5 entry).
/dev/disk/by-label/DATA /srv/dev-disk-by-label-DATA ext4 defaults,nofail,user_xattr,noexec,usrjquota=aquota.user,grpjquota=aquota.group,jqfmt=vfsv0,acl 0 2
What could be the issue that a mounted device will be unmounted by adding another USB mass storage device?
Is this linux behaviour (I have not observed this on other linux systems yet)?
Docker is mapped to NAS HDD, too, that means that there exists open files during unmount!?
I use OMV 5.4.7-1 with Kernel 4.19.97 (OMV default).
BTW: I am able to mount the device with OMV5 UI (e.g. sdb1) -> configuration change. Using apply the drive will only be mounted when it appears with the same name, e.g. sdb1. This is not the case after reboot without the backup HDD. Nevertheless the ACL UI will not work and show error messages that sda1 is not available.