I have this same result, with use_lvmetad=1 in lvm.conf. I think this is a dupe of #774082.
I have an LVM PV on /dev/md0. I noticed that ID_FS_TYPE wasn't set on it and that 69-lvm-metad.rules, which normally calls pvscan --cache on devices, requires ID_FS_USAGE to be set to LVM2_member|LVM1_member in order to proceed. This is normally set by 63-md-raid-arrays.rules, but it does not do so on Debian due to a patch added by Michael Tokarev in 2013: https://anonscm.debian.org/cgit/pkg-mdadm/mdadm.git/commit/debian/patches/use-external-blkid.diff?id=4b8076c851018afdd46a93aff38fde8f0530efb5 If I modify the behavior to still use external blkid but not include the '-u noraid' option (patch attached; needs to be modified to apply to the package though), then it works fine. -u noraid otherwise suppresses the output of any information related to LVM since I guess that counts as a RAID to blkid. I don't think this has a negative impact on any other rules since very few things read the ID_FS_* keys, but it's possible the -u noraid was set for some good reason. I assume that using the external blkid was also done for a good reason, though unfortunately none is given in the commit message - perhaps there was some relevant mailing list discussion at the time. I'd be in favor of using the builtin blkid if possible, though, as forking unneeded forks is pretty much always the right decision. Cheers, Michael
--- /lib/udev/rules.d/63-md-raid-arrays.rules 2014-12-20 04:44:19.000000000 -0500 +++ /etc/udev/rules.d/63-md-raid-arrays.rules 2015-07-31 22:23:43.927381240 -0400 @@ -26,7 +26,7 @@ ENV{DEVTYPE}=="partition", ENV{MD_DEVNAME}=="*[^0-9]", SYMLINK+="md/$env{MD_DEVNAME}%n" ENV{DEVTYPE}=="partition", ENV{MD_DEVNAME}=="*[0-9]", SYMLINK+="md/$env{MD_DEVNAME}p%n" -IMPORT{program}="/sbin/blkid -o udev -p -u noraid $tempnode" +IMPORT{program}="/sbin/blkid -o udev -p $tempnode" ENV{ID_FS_USAGE}=="filesystem|other|crypto", ENV{ID_FS_UUID_ENC}=="?*", SYMLINK+="disk/by-uuid/$env{ID_FS_UUID_ENC}" ENV{ID_FS_USAGE}=="filesystem|other", ENV{ID_FS_LABEL_ENC}=="?*", SYMLINK+="disk/by-label/$env{ID_FS_LABEL_ENC}"