Comment 1 for bug 1579586

Please attach the full logs for boot (you may need to boot with "verbose" tacked on to the kernel command-line); including full logs for the deployment via MAAS might help too.

multipath setup should be happening before LVM; and requires the multipath-boot package to be installed. It's not unlikely for LVM to fail to find "mpath0" in the case where multipath did not bring up the devices since all these names will come straight from device-mapper.

Furthermore, this looks slightly off. On Xenial, the first multipath device node should be (by default, unless this was changed by configuration) named "mpatha", not "mpath0".