pvresize after pvcreate changes PV size: expected?

[Tilman Vogel <tilman.vogel@xxxxxxxxx>]

Hi!

I just encountered the following and do not understand it. The confusing part is that when I run pvresize without size parameter directly after pvcreate, the size still seems to change even though pvcreate of course also uses the underlying device size just as pvresize should.

I am attaching the test.sh for your reference.

What am I missing?

Tilman

# ./test.sh  
+ set -o errexit
+ truncate -s 100M image
++ losetup --show -f image
+ LOOP=/dev/loop0
+ echo 'LOOP /dev/loop0'
LOOP /dev/loop0
+ pvcreate /dev/loop0
 Physical volume "/dev/loop0" successfully created.
 Not creating system devices file due to existing VGs.
+ vgcreate test /dev/loop0
 Not creating system devices file due to existing VGs.
 Volume group "test" successfully created
+ pvdisplay --units b /dev/loop0
 --- Physical volume ---
 PV Name               /dev/loop0
 VG Name               test
 PV Size               104857600 B  / not usable 4194304 B  
 Allocatable           yes  
 PE Size               4194304 B  
 Total PE              24
 Free PE               24
 Allocated PE          0
 PV UUID               zNLgIe-S8Zq-1DF5-0BhR-oGGS-q9Vy-FzNnoT
   
+ pvs --units b -o pv_all /dev/loop0
 Fmt  PV UUID                                DevSize    PV         Maj Min PMdaFree  PMdaSize  PExtVsn 1st PE   PSize      PFree      Used Attr Allocatable Exported   Missing    PE  Alloc PV Tags #PMda #PMdaUse BA Start BA Size PInUse Duplicate DeviceID DeviceIDType
 lvm2 zNLgIe-S8Zq-1DF5-0BhR-oGGS-q9Vy-FzNnoT 104857600B /dev/loop0   7   0   520704B  1044480B       2 1048576B 100663296B 100663296B   0B a--  allocatable                        24     0             1        1       0B      0B   used                                 
+ echo RESIZE
RESIZE
+ pvresize /dev/loop0
 Physical volume "/dev/loop0" changed
 1 physical volume(s) resized or updated / 0 physical volume(s) not resized
+ pvdisplay --units b /dev/loop0
 --- Physical volume ---
 PV Name               /dev/loop0
 VG Name               test
 PV Size               103809024 B  / not usable 3145728 B  
 Allocatable           yes  
 PE Size               4194304 B  
 Total PE              24
 Free PE               24
 Allocated PE          0
 PV UUID               zNLgIe-S8Zq-1DF5-0BhR-oGGS-q9Vy-FzNnoT
   
+ pvs --units b -o pv_all /dev/loop0
 Fmt  PV UUID                                DevSize    PV         Maj Min PMdaFree  PMdaSize  PExtVsn 1st PE   PSize      PFree      Used Attr Allocatable Exported   Missing    PE  Alloc PV Tags #PMda #PMdaUse BA Start BA Size PInUse Duplicate DeviceID DeviceIDType
 lvm2 zNLgIe-S8Zq-1DF5-0BhR-oGGS-q9Vy-FzNnoT 104857600B /dev/loop0   7   0   520704B  1044480B       2 1048576B 100663296B 100663296B   0B a--  allocatable                        24     0             1        1       0B      0B   used                                 
+ echo CLEANUP
CLEANUP
+ vgremove test
 Volume group "test" successfully removed
+ pvremove /dev/loop0
 Labels on physical volume "/dev/loop0" successfully wiped.
+ losetup -d /dev/loop0

Attachment: test.sh
Description: application/shellscript