Thomas Bächler wrote:

With `lvm2 2.02.98-3`, we now utilize `lvmetad` to activate LVM volumes automatically. This implies the following changes:

* The `lvm2` initramfs hook now requires the `udev` hook.

* The `use_lvmetad = 1` must be set in `/etc/lvm/lvm.conf`. This is the default now - if you have a `lvm.conf.pacnew` file, you **must** merge this change.

* You can restrict the volumes that are activated automatically by setting the `auto_activation_volume_list` in `/etc/lvm/lvm.conf`. If in doubt, leave this option **commented out**.

* If you need monitoring (needed for snapshots), run `systemctl enable lvm- monitoring.service`.

* The `lvmwait` kernel command line option is no longer needed and has no effect.

URL: https://www.archlinux.org/news/changes-to-lvm/