[linux-lvm] Unusually long boot times with LVM Snapshots

[Sreyan Chakravarty]

On Mon, Nov 23, 2020 at 6:43 PM Bryn M. Reeves <bmr at redhat.com> wrote:

> This is a classic (aka CoW/copy-on-write or "thick") snapshot since it
> was created with a size (-L 70GB). When creating a thin snapshot you do
> not specify a size for the snapshot LV - it consumes space from the
> associated thin pool as needed.
>
> Generally you can find information about the LVs on your system using
> the "lvs" command. The "Attr" field displays lv attributes including the
> volume type - see the NOTES section of 'man lvs' for the meaning of the
> values. The lvs report can also show you whether a snapshot is using CoW
> or thinp and the amount of data it is consuming.
>

I have now migrated to thin snapshots:

These are my logical volumes:

#  lvs

 LV     VG       Attr       LSize   Pool   Origin Data%  Meta%  Move Log
Cpy%Sync Convert
  fedora vgfedora Vwi-a-tz-- 700.00g pool00        16.61

  pool00 vgfedora twi-aotz-- 929.75g               12.50  16.61



But I am unable to boot now due to these errors:

Nov 24 10:44:00 localhost.HPNotebook dracut-initqueue[861]: Scanning
devices dm-0  for LVM logical volumes vgfedora/fedora
Nov 24 10:44:00 localhost.HPNotebook dracut-initqueue[886]: inactive
'/dev/vgfedora/pool00' [929.75 GiB] inherit
Nov 24 10:44:00 localhost.HPNotebook dracut-initqueue[886]: inactive
'/dev/vgfedora/fedora' [700.00 GiB] inherit
Nov 24 10:44:00 localhost.HPNotebook dracut-initqueue[888]: modprobe:
FATAL: Module dm-thin-pool not found in directory
/lib/modules/5.8.18-200.fc32.x86_64
Nov 24 10:44:00 localhost.HPNotebook dracut-initqueue[888]:
/usr/sbin/modprobe failed: 1
Nov 24 10:44:00 localhost.HPNotebook dracut-initqueue[888]: Can't process
LV vgfedora/fedora: thin target support missing from kernel?

I have tried to mark the volumes as active by :

                lvchange -kn vgfedora/pool00
                lvchange -kn vgfedora/fedora

But no change.



How do I add the dm-thin-pool module ? I can't even boot.

-- 
Regards,
Sreyan Chakravarty
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