Remove a Physical Volume listed as an “unknown device” is one of the most known issues for an Linux administrator, and that happen when LVM has scanned the storage stack, but it is unable to find a required
PV UUID . also happen when the physical volume was not removed from the volume group first while the disk was already remove from the system .
Let me tell you. how i have fixed it .
My volume group called vgora and long time i have removed the disk (LUN) and forgot to remove the disk from the volume group
The missing physical volume is part of vgora group , you can show that with command pvscan and pvdisplay
Now please clean the unknow physical volumes from vgora
# vgreduce <volume_group_name> --removemissing
In my case
#vgreduce vgora --removemissing
Redhat dont advice to use –force option
Now Check again:
Diplay the physical volumes
# pvdisplay --- Physical volume --- PV Name /dev/mapper/mpatha2 VG Name vg00 PV Size 49.51 GiB / not usable 3.00 MiB Allocatable yes PE Size 4.00 MiB Total PE 12674 Free PE 898 Allocated PE 11776 PV UUID WApBv4-TU6A-bq7h-HrYz-D76d-Q6Bq-73xOHG --- Physical volume --- PV Name /dev/mapper/oracle VG Name vgora PV Size 200.00 GiB / not usable 3.00 MiB Allocatable yes (but full) PE Size 4.00 MiB Total PE 51199 Free PE 0 Allocated PE 51199 PV UUID 32jutv-K2WS-6ES3-g3pg-ZhhN-m23z-1Q3bz0 --- Physical volume --- PV Name /dev/mapper/export VG Name vgexport PV Size 300.00 GiB / not usable 4.00 MiB Allocatable yes (but full) PE Size 4.00 MiB Total PE 76799 Free PE 0 Allocated PE 76799 PV UUID aEfq5E-Qtno-t1ug-TNEB-wyKg-EwSh-YhD0Ov
scan the physical volumes with command pvscan
# pvs PV VG Fmt Attr PSize PFree /dev/mapper/export vgexport lvm2 a-- 300.00g 0 /dev/mapper/mpatha2 vg00 lvm2 a-- 49.51g 3.51g /dev/mapper/oracle vgora lvm2 a-- 200.00g 0
Looks very fine now, the Unknow pv is gone !!.