I have storage for my OMV to an iSCSI target. Everything working great. I thought I'd disconnect the iSCSI during the week when I'm not using the storage so the disk array can spin down (saving heat and energy).
I first stopped the samba service so the mount isn't in use:
service samba stop
I then dismount the storage:
I then logout of the iSCSI target
iscsiadm -m node -u
cool, the disks spin down.
So then I reconnect:
iscsiadm -m node -l
but now my LVM is completely empty! The physical disks are there, but the Logical Volume Management pages are completely empty! lvscan doesn't do anything.