Hi, I know what is going on: there is some kind of a replay of the snapshot being performed when booting. This results into increasing boot times on increasing snapshot allocation.
I've tested this with a virtual client with incremental blocks changed on a LV which being the source of a snapshot LV. Upon bootup I could detect incremental blocks read on the snapshot COW LV (the largest user) (log the results of iostat in /etc/rc.local). When switching off caching on the client disk I could indeed detect incremental boot times with incremental blocks changed. This up to a point where the boot process stalls due to a timeout requiring manual intervention. (snapshot replay continues in the background). When in a good state a replay of the snapshot should not be required (in my opinion). I guess some kind of journaling is going on within LVM2, requiring at most the last (couple of) transaction(s) on a snapshot to be replayed, not the complete snapshot. This may need to be reported upstream (which I will do when no other comments here). Greetings, Gerben -- 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/1651838 Title: bootup halted, lvms NOT active, one LV lost Status in lvm2 package in Ubuntu: New Bug description: Hi, The bootup process is stopping in 'emergency mode', I have to manually intervene and perform a 'vgchange -a y' and after 3.5 minutes 6 logical volumes are active (however I do have 7). Only then I can finalize the boot process. Subsequent (all) boots I have to intervene. lvdisplay fails to show one logical volume, which is shown under /dev/mapper. This volume is not used, just contained some offline data. I also had an unplanned reboot a few days ago on the machine without having it under a load. The lost LV was not in use at that time (has not been mounted for a long time). I've got one snapshot defined, which acts as a mirror (LV Size same as origin), with only 4.31 % allocated to that snapshot. When viewing the system with a live desktop only the 'cow' LV is shown under /dev/mapper, none of the other LV's. Why is this unused LV lost? The data on the 'lost' LV is not needed at the moment. I'll leave things 'as is' for the moment for investigation. ProblemType: Bug DistroRelease: Ubuntu 16.04 Package: lvm2 2.02.133-1ubuntu10 ProcVersionSignature: Ubuntu 4.4.0-57.78-generic 4.4.35 Uname: Linux 4.4.0-57-generic x86_64 ApportVersion: 2.20.1-0ubuntu2.4 Architecture: amd64 Date: Wed Dec 21 19:25:22 2016 InstallationDate: Installed on 2016-06-01 (202 days ago) InstallationMedia: Ubuntu-Server 16.04 LTS "Xenial Xerus" - Release amd64 (20160420.3) ProcEnviron: LANGUAGE=en_US:en TERM=xterm PATH=(custom, no user) LANG=en_US.UTF-8 SHELL=/bin/bash SourcePackage: lvm2 UpgradeStatus: No upgrade log present (probably fresh install) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/lvm2/+bug/1651838/+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
