LVM から "Cannot use device with duplicates" と報告される

Issue

• VG を拡張しようとすると、次のエラーが生成されます。

# vgextend example_vg /dev/mapper/mpatha
  Error vgextend : Cannot use device /dev/mapper/mpatha with duplicates.
  WARNING: Not using lvmetad because duplicate PVs were found.
  WARNING: Use multipath or vgimportclone to resolve duplicate PVs?
  WARNING: After duplicates are resolved, run "pvscan --cache" to enable lvmetad.
  WARNING: PV xxxxxx-xxxx-xxxx-xxxx-xxxx-xxxx-xxxxx on /dev/sdx was already found on /dev/sdy.
  WARNING: PV xxxxxx-xxxx-xxxx-xxxx-xxxx-xxxx-xxxxx on /dev/sdy was already found on /dev/sdz.
  WARNING: PV xxxxxx-xxxx-xxxx-xxxx-xxxx-xxxx-xxxxx on /dev/sdz was already found on /dev/mapper/mpatha.
<...>
 Cannot use device /dev/mapper/mpatha with duplicates.

• 新しいボリュームグループを作成しようとすると、Cannot use device /dev/mapper/mpatha with duplicates というエラーが発生します。