498368,50> sudo pvmove -n dirac/home /dev/sda2 /dev/sdb1
  /run/lvm/lvmpolld.socket: connect failed: No such file or directory
  WARNING: Failed to connect to lvmpolld. Proceeding with polling without using lvmpolld.
  WARNING: Check global/use_lvmpolld in lvm.conf or the lvmpolld daemon state.
  /dev/sda2: Moved: 0.01%

Hmm, did it start (sysvinit system here)?

498325,26> l /etc/rc*/*lvm*
lrwxrwxrwx 1 root root 22 Jun 16  2017 /etc/rc0.d/K01lvm2-lvmetad -> ../init.d/lvm2-lvmetad
lrwxrwxrwx 1 root root 23 Jun 16  2017 /etc/rc0.d/K01lvm2-lvmpolld -> ../init.d/lvm2-lvmpolld
lrwxrwxrwx 1 root root 22 Jun 16  2017 /etc/rc1.d/K01lvm2-lvmetad -> ../init.d/lvm2-lvmetad
lrwxrwxrwx 1 root root 23 Jun 16  2017 /etc/rc1.d/K01lvm2-lvmpolld -> ../init.d/lvm2-lvmpolld
lrwxrwxrwx 1 root root 22 Oct 17 17:27 /etc/rc2.d/S02lvm2-lvmetad -> ../init.d/lvm2-lvmetad
lrwxrwxrwx 1 root root 23 Oct 17 17:27 /etc/rc2.d/S02lvm2-lvmpolld -> ../init.d/lvm2-lvmpolld
lrwxrwxrwx 1 root root 22 Oct 17 17:27 /etc/rc3.d/S02lvm2-lvmetad -> ../init.d/lvm2-lvmetad
lrwxrwxrwx 1 root root 23 Oct 17 17:27 /etc/rc3.d/S02lvm2-lvmpolld -> ../init.d/lvm2-lvmpolld
lrwxrwxrwx 1 root root 22 Oct 17 17:27 /etc/rc4.d/S02lvm2-lvmetad -> ../init.d/lvm2-lvmetad
lrwxrwxrwx 1 root root 23 Oct 17 17:27 /etc/rc4.d/S02lvm2-lvmpolld -> ../init.d/lvm2-lvmpolld
lrwxrwxrwx 1 root root 22 Oct 17 17:27 /etc/rc5.d/S02lvm2-lvmetad -> ../init.d/lvm2-lvmetad
lrwxrwxrwx 1 root root 23 Oct 17 17:27 /etc/rc5.d/S02lvm2-lvmpolld -> ../init.d/lvm2-lvmpolld
lrwxrwxrwx 1 root root 22 Jun 16  2017 /etc/rc6.d/K01lvm2-lvmetad -> ../init.d/lvm2-lvmetad
lrwxrwxrwx 1 root root 23 Jun 16  2017 /etc/rc6.d/K01lvm2-lvmpolld -> ../init.d/lvm2-lvmpolld
lrwxrwxrwx 1 root root 14 Oct 17 17:27 /etc/rcS.d/S06lvm2 -> ../init.d/lvm2

yep:

498481,6> sudo less /var/log/boot
...
Thu Jan  4 03:52:03 2018: [....] Starting LVM2 poll daemon: lvmpolld^[[?25l^[[?1c^[7^[[1G[^[[32m ok ^[[39;49m^[8^[[?25h^[[?0c.
Thu Jan  4 03:52:03 2018: /dev/mcelog not active
Thu Jan  4 03:52:03 2018: [....] Starting LVM2 metadata daemon: lvmetad^[[?25l^[[?1c^[7^[[1G[^[[32m ok ^[[39;49m^[8^[[?25h^[[?0c.
...

No other failure log messages in /var/log/messages

But yet, no lvmpoll:

498327,28> sudo ls -lA /run/lvm
total 0
srwx------ 1 root root 0 Jan  4 03:52 lvmetad.socket
0-0-15:00:34, Thu Jan 04 tconnors@dirac:~ (bash)

ok, let's restart it:

498328,29> sudo /etc/init.d/lvm2-lvmpolld restart
[ ok ] Restarting LVM2 poll daemon: lvmpolld.
0-0-15:00:43, Thu Jan 04 tconnors@dirac:~ (bash)
498329,30> ps axuf | grep lvm
root      3204  0.0  0.0 248508   796 ?        Ssl  03:52   0:00 /sbin/lvmetad
tconnors 17249  0.0  0.0  20164  3000 pts/11   S+   03:56   0:00              |       |           \_ man lvmcache
tconnors 26929  0.0  0.0  20164  3072 pts/13   S+   04:36   0:00              |       |           \_ man lvmcache
tconnors 18076  0.0  0.0  11508  1000 pts/19   S+   15:00   0:00  |           \_ grep --color=auto lvm
root     17977  0.0  0.0  27308   228 ?        Ss   15:00   0:00 /sbin/lvmpolld -t 60
0-0-15:00:47, Thu Jan 04 tconnors@dirac:~ (bash)
498330,31> sudo ls -lA /run/lvm
total 0
srwx------ 1 root root 0 Jan  4 03:52 lvmetad.socket
srwx------ 1 root root 0 Jan  4 15:00 lvmpolld.socket

Hello,

We recently ran into the same issue and discovered the reason:
lvmlockds init script for systemd, which is used more often, depends on
the systemd socket /run/lvm/lvmpolld.socket and starts lvmpolld on
demand when the socket is used.
the commandline in lvm2-lvmpolld.service is:
/sbin/lvmpolld -t 60 -f
or, more verbose:
/sbin/lvmpolld --timeout 60 --foreground
The sysvinit script /etc/init.d/lvm2-lvmpolld omits the foreground
option but keeps the timeout.
In effect lvmpolld exits after 60s of inactivity but in contrast to
systemd with sysvinit one has to manually restart the daemon.
I'd suggest one of two fixes for this:
1) replace in /etc/init.d/lvm2-lvmpolld line 70 'DAEMON_ARGS="-t 60"' by
'DAEMON_ARGS=""'
2) replace 'DAEMON_ARGS="-t 60"' by 'DAEMON_ARGS="--timeout 60"' to make
the script and running comman, for example seen by ps aux, more verbose.
I'd also suggest to note this in the lvmpolld manpage.

Hope i can help to fix this.
Best regards,
Valentin