On 4.3 pve LVM volume groups are inactive at boot

jdw

Renowned Member
Sep 22, 2011
117
4
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We have reinstalled two Proxmox 3.x machines to 4.3 and on both machines, after the install, they come up with this error when booting:

Loading, please wait...
Volume group "pve" not found
Cannot process volume group pve
Unable to find LVM volume pve/root
Gave up waiting for root device. Common problems:
...
ALERT! /dev/mapper/pve-root does not exist. Dropping to a shell!

Upon investigation, the volumes are inactive:

(initramfs) lvm
lvm> lvscan
inactive '/dev/pve/swap' [3.62 GiB] inherit
inactive '/dev/pve/root' [7.25 GiB] inherit
inactive '/dev/pve/data' [15.20 GiB] inherit
lvm> vgchange -a y pve
/sbin/modprobe failed: 1
Cannot read thin-pool target version.
Can't process LV data: thin-pool target support missing from kernel?
2 logical volume(s) in volume group "pve" now active
lvm> exit
Exiting.
(initramfs) exit

(The machines boot normally at this point. Until next boot, when the volumes are inactive again.)

The boot device for both is a small (32GiB) SATA SSD.

Is this a bug with 4.3? It has never occurred with any previous 3.x or 4.1 version on this same hardware. (We have four others just like these running 4.1 with no problem.)

Nothing unique or custom was done during the install.
 
This happens to me on almost every install, either with an install to LVM or to ZFS root file systems. Its worse with slow media such as sdcards or thumbdrives but can happen to any media. some kernel versions make it worse, some better.

The solution is to increase delay to root initialization by adding "rootdelay=8" to the /etc/default/grub line that reads "GRUB_CMDLINE_LINUX=", where 8 is the delay to mount the root file system in seconds.

you can do it with the following commands (run as root:)

sed -i.bak 's/^GRUB_CMDLINE_LINUX="/& rootdelay=8 /' /etc/default/grub
update-grub

Devs- this should probably be done by default at installation.
 
Hmm, I wouldn't regard these SSD's as particularly slow, and the same machines did work with previous versions with no trouble, but I will certainly give that a shot.

Thanks for the suggestion!
 
Hmm, I wouldn't regard these SSD's as particularly slow, and the same machines did work with previous versions with no trouble, but I will certainly give that a shot.

Thanks for the suggestion!

the question is not whether the disks are slow (they can be super fast whatever devices), but whether the device initialization (including layers on top like LVM) is slow.
 

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