Re: [linux-lvm] [PATCH 1/1] pvscan: wait for udevd

[Oleksandr Natalenko <oleksandr@redhat.com>]

Hi.

(will comment only on what I can comment, dropping the rest)

On Thu, Feb 18, 2021 at 04:19:01PM +0100, Martin Wilck wrote:
> > I'm not sure this issue is reproducible with any kind of LVM layout.
> > What I have is thin-LVM-on-LUKS-on-LVM:
> 
> I saw MD in your other logs...?

FWIW, one of the machines have soft RAID, another does not, the issue
is reproducible regardless of whether there's soft RAID or not.

> > Feb 10 17:24:26 archlinux lvm[643]:   pvscan[643] VG sys run
> > autoactivation.
> > Feb 10 17:24:26 archlinux lvm[643]:   /usr/bin/dmeventd: stat failed:
> > No such file or directory
> 
> What's going on here? pvscan trying to start dmeventd ? Why ? There's a
> dedicated service for starting dmeventd (lvm2-monitor.service). I can
> see that running dmeventd makes sense as you have thin pools, but I'm
> at a loss why it has to be started at that early stage during boot
> already.
> 
> This is a curious message, it looks as if pvscan was running from an
> environment (initramfs??) where dmeventd wasn't available. The message
> is repeated, and after that, pvscan appears to hang...

Not sure either. FWIW, real root is on a thin volume (everything is,
in fact, except /boot and swap).

> > Feb 10 17:24:26 archlinux lvm[720]:   pvscan[720] PV /dev/md0 online.
> > Feb 10 17:24:26 archlinux lvm[643]:   /usr/bin/dmeventd: stat failed:
> > No such file or directory
> > Feb 10 17:24:26 archlinux lvm[643]:   WARNING: Failed to monitor
> > sys/pool.
> > Feb 10 17:24:56 spock systemd[1]: lvm2-pvscan@253:2.service: State
> > 'stop-sigterm' timed out. Killing.
> > Feb 10 17:24:56 spock systemd[1]: lvm2-pvscan@253:2.service: Killing
> > process 643 (lvm) with signal SIGKILL.
> > Feb 10 17:24:56 spock systemd[1]: lvm2-pvscan@253:2.service: Main
> > process exited, code=killed, status=9/KILL
> > Feb 10 17:24:56 spock systemd[1]: lvm2-pvscan@253:2.service: Failed
> > with result 'timeout'.
> > Feb 10 17:24:56 spock systemd[1]: Stopped LVM event activation on
> > device 253:2.
> 
> So what's timing out here is the attempt to _stop_ pvscan. That's
> curious. It looks like a problem in pvscan to me, not having reacted to
> a TERM signal for 30s.
> 
> It's also worth noting that the parallel pvscan process for device 9:0
> terminated correctly (didn't hang).

Yes, pvscan seems to not react to SIGTERM. I have
DefaultTimeoutStopSec=30s, if I set this to 90s, pvscan hangs for 90s
respectively.

-- 
  Best regards,
    Oleksandr Natalenko (post-factum)
    Principal Software Maintenance Engineer

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