Failed unmounting /var when it is a separate filesystem

[André Burkhardt]

In a fresh install of Ubuntu Server 18.04.1 LTS with the /var-Filesystem on a separate partition (LVM), there are Errors on shutdown/reboot (Failed unmounting /var).

1) The release
Release: Ubuntu 18.04.1 LTS

2) The version
Version:apt-cache policy systemd
systemd: Installed: 237-3ubuntu10.12
          Candidate: 237-3ubuntu10.12

3) What you expected to happen
Clean unmount of /var Filesystem without Failure

4) What happened instead
Console output on shutdown/reboot
[...]
[ OK ] Stopped Flush Journal to Persistent Storage.
[ OK ] Stopped target Local File Systems.
         Unmounting /boot...
         Unmounting /var...
         Unmounting /run/user/1000...
[FAILED] Failed unmounting /var.
[ OK ] Stopped File System Check on /dev/mapper/vg_system-lv_var.
[ OK ] Unmounted /run/user/1000
[...]

Extract from journalctl
[...]
Feb 07 13:13:31 xxxxx systemd[1]: Stopped Flush Journal to Persistent Storage.
Feb 07 13:13:31 xxxxx systemd[1]: Stopped target Local File Systems.
Feb 07 13:13:31 xxxxx systemd[1]: Unmounting /boot...
Feb 07 13:13:31 xxxxx systemd[1]: Unmounting /var...
Feb 07 13:13:31 xxxxx systemd[1]: Unmounting /run/user/1000...
Feb 07 13:13:31 xxxxx umount[1775]: umount: /var: target is busy.
Feb 07 13:13:31 xxxxx systemd[1]: var.mount: Mount process exited, code=exited status=32
Feb 07 13:13:31 xxxxx systemd[1]: Failed unmounting /var.
Feb 07 13:13:31 xxxxx systemd[1]: Stopped File System Check on /dev/mapper/vg_system-lv_var.
Feb 07 13:13:31 xxxxx systemd[1]: Unmounted /run/user/1000.
[...]

Applying the changes described here:

https://github.com/systemd/systemd/issues/867#issuecomment-250202183

let the Error-Messages go away. But are there any side-effects?

[Dan Streetman (ddstreet)]

please reopen if this is still an issue

[Nick Rosbrook (enr0n)]

According to the upstream bug report, this is fixed by https://github.com/systemd/systemd/commit/1e187d2dd52cbb4f0bb30e4d96acf7f72a145b91, which is present in Focal and newer.