I'm running an NFS server with two exports:
/mnt/sda1 192.168.1.254/255.255.255.0(rw,fsid=1,no_subtree_check,all_squash,anonuid=0,anongid=0,insecure) /mnt/sdb1 192.168.1.254/255.255.255.0(rw,fsid=1,no_subtree_check,all_squash,anonuid=0,anongid=0,insecure)
On the server if I cd to either directory they are clearly very distinct drives.
/dev/sda1 1.8T 1.7T 8.6G 100% /mnt/sda1 /dev/sdb1 2.0T 1.3T 603.9G 68% /mnt/sdb1
However if I mount these nfs shares on a client, it seems that mounting /mnt/sdb1 points to /mnt/sda1 directly.
sudo mount 192.168.1.123:/mnt/sdb1 /media/test
Then on the client with df -h
192.168.1.123:/mnt/sdb1 1.8T 1.7T 8.6G 100% /media/test
As you can see above based even on storage space alone, this is actually /mnt/sda1.
This server has been running a long time and I faintly recall ~5 years ago I was playing with lvm disk managing stuff (but never got it working) and may have configured something that is resulting in this weird behaviour - but I'm not sure. I'm not even really sure where to begin as this is a hard behaviour to google. Help is appreciated!