If you allocate the one volume to one VM and you did created PV after that you did dettach the volume without unmounting the volume.
So here is the procedure how to troubleshoot with it.
[root@localhost ~]# pvdisplay
--- Physical volume ---
PV Name /dev/sda2
VG Name VolGroup00
PV Size 19.89 GB / not usable 19.49 MB
Allocatable yes (but full)
PE Size (KByte) 32768
Total PE 636
Free PE 0
Allocated PE 636
PV UUID KhAEcp-48eH-a3nz-HFzF-sXPt-4duo-Vl0NAa
--- Physical volume ---
PV Name unknown device
VG Name VolGroup00
PV Size 10.00 GB / not usable 32.00 MB
Allocatable yes
PE Size (KByte) 32768
Total PE 319
Free PE 319
Allocated PE 0
PV UUID 7CeL4J-wKL1-EigZ-YpWc-qufr-Gbwp-UcFOne
[root@localhost ~]# vgreduce --removemissing --force
Now just check following things.. your issue is resolved.
[root@localhost ~]# vgdisplay
--- Volume group ---
VG Name VolGroup00
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 4
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 2
Open LV 2
Max PV 0
Cur PV 2
Act PV 1
VG Size 29.84 GB
PE Size 32.00 MB
Total PE 955
Alloc PE / Size 636 / 19.88 GB
Free PE / Size 319 / 9.97 GB
VG UUID 7o4aWW-Euef-k2Ti-n4rt-QTB0-6RZr-4u7Y9w
