Bug#867368: systemd-udevd: delays boot for 2+ minutes when LVM PV is inside a LV

[Rob Leslie]

> On Jul 6, 2017, at 8:03 AM, Felipe Sateler <fsateler at debian.org> wrote:
> 
> > % systemd-analyze
> > Startup finished in 2min 55.491s (kernel) + 13.076s (userspace) = 3min 8.568s
> 
> This suggests the kernel is the one slowing things down.

I initially thought so too, but attempts to debug the kernel with e.g.
'initcall_debug' were not fruitful. Instead indications point to something
happening in early initramfs userspace.

> Can you try booting with the old jessie kernel? This looks like a kernel regression.

I have confirmed that the problem still exists even when booting a stretch
system using the most recent jessie kernel.

I have tried modifying the initramfs scripts to arrange for systemd-udevd to be
passed the '--debug' option. Here are some relevant excerpts:

> % grep 793 systemd-udevd.debug
> seq 793 queued, 'change' 'block'
> seq 793 running
> seq 793 '/devices/virtual/block/dm-2' is taking a long time

> % tail -n 5 systemd-udevd.debug 
> giving up waiting for workers to finish
> event loop failed: Connection timed out
> Unload module index
> Unloaded link configuration context.
> timeout '/sbin/lvm pvscan --cache --activate ay --major 253 --minor 2'


This of course suggests the problem may actually lie with lvm2. Please feel free
to reassign if you agree, or suggest a further course of investigation.

Thanks.

-- 
Rob Leslie
rob at mars.org