The apparent cause seems to be lvm2 (2.02.133-1ubuntu8). From the Changelog (https://launchpad.net/ubuntu/xenial/+source/lvm2/+changelog)
lvm2 (2.02.133-1ubuntu8) xenial; urgency=medium * Drop debian/85-lvm2.rules. This is redundant now, VGs are already auto-assembled via lvmetad and 69-lvm-metad.rules. This gets rid of using watershed, which causes deadlocks due to blocking udev rule processing. (LP: #1560710) * debian/rules: Put back initramfs-tools script to ensure that the root and resume devices are activated (lvmetad is not yet running in the initrd). * debian/rules: Put back activation systemd generator, to assemble LVs in case the admin disabled lvmetad. * Make debian/initramfs-tools/lvm2/scripts/init-premount/lvm2 executable and remove spurious chmod +x Ubuntu delta in debian/rules. -- Martin Pitt <martin.p...@ubuntu.com> Wed, 30 Mar 2016 10:56:49 +0200 The initramfs-tools script does not activate all of the logical volumes and its detection is lacking in certain edge cases like mine. -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to lvm2 in Ubuntu. https://bugs.launchpad.net/bugs/1573982 Title: LVM boot problem - volumes not activated after upgrade to Xenial Status in lvm2 package in Ubuntu: Confirmed Bug description: Soon after upgrade to Xenial (from 15.10) the boot process got broken. I'm using LVM for /root swap and other partitions. === The current behaviour is: When I boot short after the Grub login screen I'm getting log messages like: --- Scanning for Btrfs filesystems resume: Could not state the resume device file: '/dev/mapper/VolGroup....' Please type in the full path... --- Then I press ENTER, for a few minutes some errors about floppy device access are raised (for some reason it tries to scan fd0 when floppy drive is empty). And then: --- Gave up waiting for root device. Common problems: ... ... ALERT! UUID=xxx-xxx.... does not exist. Dropping to a shell. --- From the BusyBox shell I managed to recover the boot by issuing "lvm vgchange -ay", then exit and then boot continues fine (all LVM file systems are successfully mounted). === One workaround so far is creating /etc/initramfs-tools/scripts/local-top/lvm2-manual script doing "lvm vgchange -ay". But I'm looking for cleaner solution. Boot used to work fine with 15.10. Actually the first boot after upgrading to Xenial actually worked OK too, I'm not sure what might changed meanwhile (I've been fixing some packages installation since mysql server upgrade has failed). === # lsb_release -rd Description: Ubuntu 16.04 LTS Release: 16.04 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/lvm2/+bug/1573982/+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