Recovering a Lost LVM Volume Disk

# pvscan
  Couldn't find device with uuid '56ogEk-OzLS-cKBc-z9vJ-kP65-DUBI-hwZPSu'.
# pvcreate --uuid 56ogEk-OzLS-cKBc-z9vJ-kP65-DUBI-hwZPSu /dev/sdc
# vgscan
...

https://www.novell.com/coolsolutions/appnote/19386.html

Extend lv size

1. pvcreate /dev/sdb1
2. vgextend myvg /dev/sdb1
3. lvextend -l +100%FREE /dev/myvg/testlv
4. resize2fs /dev/myvg/testlv