pvremove wipes the label on a device so that LVM will no longer recognise
it as a PV.
.P
A PV cannot be removed from a VG while it is used by an active LV.
.P
Repeat the force option (\fB-ff\fP) to forcibly remove a PV belonging to
an existing VG. Normally, \fBvgreduce\fP(8) should be used instead.