こんな感じでpv丸ごとコピーした場合。
PVのuuidが同じになるのでエラーとなってしまう。

dd if=/dev/xvda2 of=/dev/xvdb2

# pvs
  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 0yTzZw-rtCB-XEqN-rXsR-H9x1-BsJF-rySufQ on /dev/xvdb2 was already found on /dev/xvda2.
  WARNING: PV 0yTzZw-rtCB-XEqN-rXsR-H9x1-BsJF-rySufQ prefers device /dev/xvda2 because device is used by LV.
  PV         VG     Fmt  Attr PSize  PFree 
  /dev/xvda2 centos lvm2 a--  19.51g 40.00m

vgimportclone でuuidを変更してあげると、治ります。

LVをマウントしたままだと実行できない。

# vgimportclone /dev/xvda1
  WARNING: PV 0yTzZw-rtCB-XEqN-rXsR-H9x1-BsJF-rySufQ on /dev/xvdb2 was already found on /dev/xvda2.
  WARNING: PV 0yTzZw-rtCB-XEqN-rXsR-H9x1-BsJF-rySufQ prefers device /dev/xvda2 because device is used by LV.
  Failed to find physical volume "/dev/xvda1".
  Failed to find all devices.
  WARNING: PV 0yTzZw-rtCB-XEqN-rXsR-H9x1-BsJF-rySufQ on /dev/xvdb2 was already found on /dev/xvda2.

アンマウント、もしくはrootディスクの場合リカバリーモードで起動後に実行してあげる。

# vgimportclone /dev/xvda2 
  WARNING: PV 0yTzZw-rtCB-XEqN-rXsR-H9x1-BsJF-rySufQ on /dev/xvdb2 was already found on /dev/xvda2.
  WARNING: PV 0yTzZw-rtCB-XEqN-rXsR-H9x1-BsJF-rySufQ prefers device /dev/xvda2 because device is used by LV.
  Device /dev/xvda2 has active LVs, deactivate first.
  WARNING: PV 0yTzZw-rtCB-XEqN-rXsR-H9x1-BsJF-rySufQ on /dev/xvdb2 was already found on /dev/xvda2.
  WARNING: Disabling lvmetad cache which does not support duplicate PVs.