Seems I have an idea. Using smitty an error message occurs when trying
to expand a lv. The error message says a disk is not listed in the ODM.
The identifier describes a disk that was removed from the system some
weeks ago. The disk was removed using unmirrorvg. Seems that not all
entries of this disk were removed from the ODM. I added the disk again
and strange things appear:

>lspv
hdisk1 002091003ec20cd7 rootvg
hdisk0 00209100668b15dc rootvg

>lsvg -p rootvg
rootvg:
PV_NAME PV STATE TOTAL PPs FREE PPs FREE
DISTRIBUTION
hdisk1 active 2170 1883
369..380..266..434..434

>reducevg rootvg hdisk0
reducevg -d rootvg hdisk0
0516-022 lquerypv: Illegal parameter or structure value.
0516-022 lquerypv: Illegal parameter or structure value.
0516-884 reducevg: Unable to remove physical volume hdisk0.

>extendvg rootvg hdisk0
0516-696 extendvg: Physical Volume hdisk0 belongs to another volume group.

This causes all the trouble. How can I remove the faulty entries from
the ODM?

Patrick