Taken from here This is put here for my reference, in case the above link ever breaks . When you use a DRBD device as an underlying block device for lvm as described in the drbd manual you may face the following error after reboot and start DRBD. Lower device is already claimed The reason is the lack of the lvm.conf in the initramfs. To add this file to the initramfs simply follow these steps: edit the file /usr/share/initramfs-tools/hooks/lvm2 and add [ -r /etc/lvm/lvm.conf ] && mkdir $DESTDIR/etc/lvm && cp /etc/lvm/lvm.conf $DESTDIR/etc/lvm after the lines contains cp -p /etc/udev/rules.d/85-lvm2.rules ${DESTDIR}/etc/udev/rules.d so that it looks like cp -p /etc/udev/rules.d/85-lvm2.rules ${DESTDIR}/etc/udev/rules.d [ -r /etc/lvm/lvm.conf ] && mkdir $DESTDIR/etc/lvm && cp /etc/lvm/lvm.conf $DESTDIR/etc/lvm then you have to rebuild the initramfs using update-initramfs -u and to restart the system in order to modifications ca...