[linux-lvm] PV corruption: allocated PE > total PE

[linux-lvm] PV corruption: allocated PE > total PE

[Toby Dickenson]

Ive just noticed that one of my PVs has more allocated PE's than the total 
available, leading to a negative amount of free space:

vrumpet root # pvdisplay -d /dev/hda5
  --- Physical volume ---
  PV Name               /dev/hda5
  VG Name               myvg
  PV Size               11.72 GB / not usable 33.65 MB
  Allocatable           yes
  PE Size (KByte)       32768
  Total PE              374
  Free PE               4294967278
  Allocated PE          392
  PV UUID               TXK2VM-UWdP-dMbY-yz4c-Nq3b-GM32-B56udb

This is on a gentoo linux system, kernel 2.6.6. The latest LVM userland in 
gentoo is 2.00.08, I havent tried anything more recent, but there doesnt seem 
anything relevant in the change log. These VGs were originally created using 
LVM1 on a 2.4 kernel.

Any suggestions?

Thanks in advance,

Re: [linux-lvm] PV corruption: allocated PE > total PE

[Alasdair G Kergon]

On Tue, Oct 12, 2004 at 08:41:14AM +0100, Toby Dickenson wrote:
> Ive just noticed that one of my PVs has more allocated PE's than the total 
> available, leading to a negative amount of free space:
 
> This is on a gentoo linux system, kernel 2.6.6. The latest LVM userland in 
> gentoo is 2.00.08, I havent tried anything more recent, but there doesnt seem 
> anything relevant in the change log. 

Definitely try the latest version: there've been a few related fixes.
(With lvm1 on-disk format, may need to backup restore/metadata if it's 
wrong on disk.)

Alasdair
-- 
agk@redhat.com

Re: [linux-lvm] PV corruption: allocated PE > total PE

[Toby Dickenson]

On Tuesday 12 Oct 2004 14:10, Alasdair G Kergon wrote:
> On Tue, Oct 12, 2004 at 08:41:14AM +0100, Toby Dickenson wrote:
> > Ive just noticed that one of my PVs has more allocated PE's than the
> > total available, leading to a negative amount of free space:
> >
> > This is on a gentoo linux system, kernel 2.6.6. The latest LVM userland
> > in gentoo is 2.00.08, I havent tried anything more recent, but there
> > doesnt seem anything relevant in the change log.
>
> Definitely try the latest version: there've been a few related fixes.

OK, I'm on lvm .25 and device mapper .19. 

I removed the newest LV in that PV, then rebooted. Everything looked right, 
and the metadata backup was as I expected. However using lvcreate again to 
create a sufficiently large LV (large enough to fill this PV plus a bit more) 
recreated the original problem in pvdisplay's output.

> (With lvm1 on-disk format, may need to backup restore/metadata if it's
> wrong on disk.)

The following values all seem to be consistent:
* pvdisplay 'Total PE'
* pe_count in /etc/lvm/backup/
* the total of the relevant 'extent_count' fields in /etc/lvm/backup/

But the value reported by pvdisplay 'Allocated PE' is too large. Where does 
pvdisplay get that value from? Do I need to worry about data corruption, or 
could this be just a display formatting bug?

Re: [linux-lvm] PV corruption: allocated PE > total PE

[Alasdair G Kergon]

I still can't reproduce this.

Please do a metadata backup/restore using 2.00.25 to make sure the
on-disk metadata is correct, then try again.

If it still goes wrong, please send me your /etc/lvm directory
to investigate.

Alasdair
-- 
agk@redhat.com