I've ruled out "nofail" & "0 0"; it seems that you are able to evade the issue by using "mapper". I don't know what it is.
Could you try booting your system (is it Ubuntu server 15.10?) with the same fstab style, but with your own partitions? # / was on /dev/sda4 during installation UUID=15417b2e-0521-486c-8dc0-9739a4b35c47 / ext4 errors=remount-ro 0 1 # /boot/efi was on /dev/sda3 during installation UUID=E48C-DDA6 /boot/efi vfat umask=0077 0 1 # swap was on /dev/sda6 during installation UUID=4870beef-bb2c-40c1-91da-f1444f90c51b none swap sw,nofail,pri=2 0 0 # swap on SSD Samsung UUID=fa2b8ce4-6ce7-4fb2-ac12-475264bed20f none swap sw,nofail,pri=1 0 0 -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to util-linux in Ubuntu. https://bugs.launchpad.net/bugs/1516225 Title: Swapon does not respect fstab priorities order Status in util-linux package in Ubuntu: Invalid Bug description: uname -a Linux msi-ge60-ubuntu 4.2.0-18-generic #22-Ubuntu SMP Fri Nov 6 18:25:50 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux sudo swapon --summary Filename Type Size Used Priority /dev/sdc2 partition 50331644 0 -1 /dev/sda6 partition 50331644 0 -2 However, in /etc/fstab: # swap was on /dev/sda6 during installation UUID=4870beef-bb2c-40c1-91da-f1444f90c51b none swap sw,nofail,pri=-1 0 0 # swap on SSD Samsung /dev/sdc2 UUID=fa2b8ce4-6ce7-4fb2-ac12-475264bed20f none swap sw,nofail,pri=-2 0 0 Does the fact that sdc2 is a SSD makes swapon override the fstab priorities? It is suspicious that swapon prints sdc2 first in the summary. despite the following facts: - sdc2 priority is -2 in fstab - sdc2 is declared after sda2 in fstab - sdc2 is after sda2 in alphabetical order To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/util-linux/+bug/1516225/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp