As you can see below, that /dev/hdb7 acquires all the PE's (which in this case is the whole operating system). Each other physical volumes physical extents that are free (none are used) equals to the total of pe's used in /dev/hdb7 30515 - 21043 = 9472.
I am using pvmove -v --alloc anywhere /dev/hdb7 to move all the physical extents off /dev/hdb7 to the other physical volumes. That being said, it just leaves this hanging
--- Physical volumes ---
PV Name /dev/hdb1
PV UUID DpcxQi-9qHf-pITK-deQ2-zbW7-8ywG-rGp7W6
PV Status allocatable
Total PE / Free PE 2386 / 2386
PV Name /dev/hdb2
PV UUID keQJS3-rbDe-kXZf-n17o-EZ5n-2Bs8-CKrPYr
PV Status allocatable
Total PE / Free PE 1194 / 1194
PV Name /dev/hdb3
PV UUID x6Vl7h-yhFr-fSE6-eaqK-EUvX-Bvcp-uOix7r
PV Status allocatable
Total PE / Free PE 1194 / 1194
PV Name /dev/hdb5
PV UUID rbHmg7-3AXC-nH4V-hfO2-mzG9-7E73-m50ndq
PV Status allocatable
Total PE / Free PE 2386 / 2386
PV Name /dev/hdb6
PV UUID IZAIeb-prQl-g3Ff-qoDD-sQti-t8di-AnoVCi
PV Status allocatable
Total PE / Free PE 478 / 478
PV Name /dev/hdb7
PV UUID QWybhr-RRBj-0Xks-LZqp-c7oC-MfC0-DZvDXH
PV Status allocatable
Total PE / Free PE 30515 / 21043
PV Name /dev/hda9
PV UUID bDkGUr-0rL8-srcF-RhIg-xrw2-byjS-CKDRkJ
PV Status allocatable
Total PE / Free PE 2433 / 2433
tuxie var # pvmove -v --alloc anywhere /dev/hdb7
Wiping cache of LVM-capable devices
Finding volume group "myvg"
Archiving volume group "myvg" metadata (seqno 33).
Creating logical volume pvmove0
Moving 2560 extents of logical volume myvg/usr
Moving 2560 extents of logical volume myvg/home
Moving 1280 extents of logical volume myvg/opt
Moving 2560 extents of logical volume myvg/var
Moving 512 extents of logical volume myvg/tmp
Found volume group "myvg"
Found volume group "myvg"
Found volume group "myvg"
Found volume group "myvg"
Found volume group "myvg"
Updating volume group metadata
Creating volume group backup "/etc/lvm/backup/myvg" (seqno 34).
Found volume group "myvg"
Found volume group "myvg"
Suspending myvg-usr (254:0)
Found volume group "myvg"
Found volume group "myvg"
Suspending myvg-home (254:1)
Found volume group "myvg"
Found volume group "myvg"
Suspending myvg-opt (254:2)
Found volume group "myvg"
Found volume group "myvg"
Suspending myvg-var (254:3)
Found volume group "myvg"
Found volume group "myvg"
Suspending myvg-tmp (254:4)
Found volume group "myvg"
Creating myvg-pvmove0
Loading myvg-pvmove0 table
Resuming myvg-pvmove0 (254:5)
Found volume group "myvg"
Loading myvg-pvmove0 table
Suppressed myvg-pvmove0 identical table reload.
Loading myvg-usr table
Resuming myvg-usr (254:0)
Found volume group "myvg"
Loading myvg-pvmove0 table
Suppressed myvg-pvmove0 identical table reload.
Loading myvg-home table
Resuming myvg-home (254:1)
Found volume group "myvg"
Loading myvg-pvmove0 table
Suppressed myvg-pvmove0 identical table reload.
Loading myvg-opt table
Resuming myvg-opt (254:2)
Found volume group "myvg"
Loading myvg-pvmove0 table
Suppressed myvg-pvmove0 identical table reload.
Loading myvg-var table
Resuming myvg-var (254:3)
Found volume group "myvg"
Loading myvg-pvmove0 table
Suppressed myvg-pvmove0 identical table reload.
Loading myvg-tmp table
Resuming myvg-tmp (254:4)
Checking progress every 15 seconds
/dev/hdb7: Moved: 0.4%
/dev/hdb7: Moved: 0.9%
/dev/hdb7: Moved: 1.3%
/dev/hdb7: Moved: 1.7%
/dev/hdb7: Moved: 2.2%
/dev/hdb7: Moved: 2.6%
/dev/hdb7: Moved: 3.0%
/dev/hdb7: Moved: 3.4%
/dev/hdb7: Moved: 3.9%
/dev/hdb7: Moved: 4.3%
/dev/hdb7: Moved: 4.7%
/dev/hdb7: Moved: 5.2%
/dev/hdb7: Moved: 5.6%
/dev/hdb7: Moved: 6.0%
/dev/hdb7: Moved: 6.5%
/dev/hdb7: Moved: 6.9%
/dev/hdb7: Moved: 7.3%
/dev/hdb7: Moved: 7.7%
/dev/hdb7: Moved: 8.2%
/dev/hdb7: Moved: 8.6%
/dev/hdb7: Moved: 9.0%
/dev/hdb7: Moved: 9.4%
/dev/hdb7: Moved: 9.8%
/dev/hdb7: Moved: 10.3%
/dev/hdb7: Moved: 10.7%
/dev/hdb7: Moved: 11.1%
/dev/hdb7: Moved: 11.5%
/dev/hdb7: Moved: 12.0%
/dev/hdb7: Moved: 12.4%
/dev/hdb7: Moved: 12.8%
/dev/hdb7: Moved: 13.3%
/dev/hdb7: Moved: 13.7%
/dev/hdb7: Moved: 14.1%
/dev/hdb7: Moved: 14.6%
/dev/hdb7: Moved: 15.0%
/dev/hdb7: Moved: 15.4%
/dev/hdb7: Moved: 15.9%
/dev/hdb7: Moved: 16.3%
/dev/hdb7: Moved: 16.7%
/dev/hdb7: Moved: 17.2%
/dev/hdb7: Moved: 17.6%
/dev/hdb7: Moved: 18.0%
/dev/hdb7: Moved: 18.4%
/dev/hdb7: Moved: 18.9%
/dev/hdb7: Moved: 19.3%
/dev/hdb7: Moved: 19.7%
/dev/hdb7: Moved: 20.2%
Updating volume group metadata
Creating volume group backup "/etc/lvm/backup/myvg" (seqno 35).
Found volume group "myvg"
Found volume group "myvg"
Suspending myvg-usr (254:0)
Suspending myvg-pvmove0 (254:5)
Found volume group "myvg"
Found volume group "myvg"
Suspending myvg-home (254:1)
Suspending myvg-pvmove0 (254:5)
Found volume group "myvg"
Found volume group "myvg"
Suspending myvg-opt (254:2)
Suspending myvg-pvmove0 (254:5)
Found volume group "myvg"
Found volume group "myvg"
Suspending myvg-var (254:3)