[linux-lvm] can't create a PV

[linux-lvm] can't create a PV

[Gunther Clasen]

Hi,

I have the following problem: I have a VG which sits on two partitions.
This VG has been created with SuSE 7.2, that is version 1 of LVM. (I
don't know exactly which one.) I wish to extend that VG and I have tried
to do that from SuSE 9.2, which runs
  LVM version:     2.00.25 (2004-09-29)
  Library version: 1.00.19-ioctl (2004-07-03)
  Driver version:  4.1.0

The type of the partition is set to Linux LVM, like the others, but it
does not work. I get this error:

# pvcreate -vv /dev/hdg9
      Setting global/locking_type to 1
      Setting global/locking_dir to /var/lock/lvm
      File-based locking enabled.
      Locking /var/lock/lvm/P_orphans WB
      Getting size of /dev/hdg9
      metadata/pvmetadatasize not found in config: defaulting to 255
      metadata/pvmetadatacopies not found in config: defaulting to 1
  /dev/hdg9: Couldn't find device.  Check your filters?
      Unlocking /var/lock/lvm/P_orphans

I can't see that the filters are a problem. The entry in
/etc/lvm/lvm.conf is:
    filter = [ "r|/dev/.*/by-path/.*|", "r|/dev/.*/by-id/.*|", "a/.*/" ]

I understand now that I should use -M1 to add this PV to an old V1 VG,
but that is not the problem. I still get the same error.

What am I doing wrong?

Any help would be appreciated.

Gunther

Re: [linux-lvm] can't create a PV

[Gunther Clasen]

On Mon, Feb 06, 2006, Gunther Clasen wrote:
> Hi,
> 
> I have the following problem: I have a VG which sits on two partitions.
> This VG has been created with SuSE 7.2, that is version 1 of LVM. (I
> don't know exactly which one.) I wish to extend that VG and I have tried
> to do that from SuSE 9.2, which runs
>   LVM version:     2.00.25 (2004-09-29)
>   Library version: 1.00.19-ioctl (2004-07-03)
>   Driver version:  4.1.0
> 
> The type of the partition is set to Linux LVM, like the others, but it
> does not work. I get this error:
> 
> # pvcreate -vv /dev/hdg9
>       Setting global/locking_type to 1
>       Setting global/locking_dir to /var/lock/lvm
>       File-based locking enabled.
>       Locking /var/lock/lvm/P_orphans WB
>       Getting size of /dev/hdg9
>       metadata/pvmetadatasize not found in config: defaulting to 255
>       metadata/pvmetadatacopies not found in config: defaulting to 1
>   /dev/hdg9: Couldn't find device.  Check your filters?
>       Unlocking /var/lock/lvm/P_orphans
> 
> I can't see that the filters are a problem. The entry in
> /etc/lvm/lvm.conf is:
>     filter = [ "r|/dev/.*/by-path/.*|", "r|/dev/.*/by-id/.*|", "a/.*/" ]
> 
> I understand now that I should use -M1 to add this PV to an old V1 VG,
> but that is not the problem. I still get the same error.
> 
> What am I doing wrong?
> 
> Any help would be appreciated.
> 
> Gunther

I have investigated this a bit further. I have booted SuSE 9.0 and done
a pvcreate /dev/hdg9 from there. It worked fine. I have then added this
PV to VG vg7, which worked fine, too.

When I then boot SuSE 9.2 again, I get the following in
/var/log/boot.msg:

<notice>run boot scripts (boot.lvm)
Scanning for LVM volume groups...
  Reading all physical volumes.  This may take a while...
  1 PV(s) found for VG vg1: expected 2
  Volume group "vg1" not found
  Found volume group "vg0" using metadata type lvm1
  2 PV(s) found for VG vg7: expected 3
  Volume group "vg7" not found
  Found volume group "vg4" using metadata type lvm1
Activating LVM volume groups...
  1 PV(s) found for VG vg1: expected 2
  Unable to find volume group "vg1"
  11 logical volume(s) in volume group "vg0" now active
  2 PV(s) found for VG vg7: expected 3
  Unable to find volume group "vg7"

VG vg1 is dead. I have no clue why it still finds traces of it on the
system. VG vg0 and vg4 are up and running. The problem is vg7, to which
I have just added /dev/hdg9. Why can't lvm find it??? /dev/hdg9 has
previously been used as part of an md device (soft raid).

Is this a bug in lvm? Or is my harddisk dying? Or what could it be?

I hope I haven't actually killed my vg7 yet... (All I did was adding the
PV, no data on it yet.)

Gunther

Re: [linux-lvm] can't create a PV

[Marcin Struzak]

Gunther Clasen wrote:
> [...] Or is my harddisk dying? 

Take a look at smartmontools (http://smartmontools.sourceforge.net/); 
they can accurately pinpoint existing or imminent hard-disk failures.

--Marcin

Re: [linux-lvm] can't create a PV

[Gunther Clasen]

On Wed, Feb 08, 2006, Marcin Struzak wrote:
> Gunther Clasen wrote:
> >[...] Or is my harddisk dying? 
> 
> Take a look at smartmontools (http://smartmontools.sourceforge.net/); 
> they can accurately pinpoint existing or imminent hard-disk failures.

Well, that is the reason for my wish to extend that VG. So that I can
copy data from my failing disk:

Feb 12 16:12:55 tui smartd[5958]: Device: /dev/hde, 4 Currently unreadable (pending) sectors
Feb 12 16:12:55 tui smartd[5958]: Device: /dev/hde, 1 Offline uncorrectable sectors

/dev/hda and /dev/hdg only report changes in attributes 8 and 209
(Seek_Time_Performance and Offline_Seek_Performnce). I don't thik that
is a problem.

I'm still quite puzzled as to why I can't crate physical volumes on
/dev/hdg9 and /dev/hdg10, when /dev/hdg7 and /dev/hdg8 work fine...
It can't possibly be down to the filters, as the program suggested?

Regards,

Gunther

Re: [linux-lvm] can't create a PV

[Jim Ford]

 > Take a look at smartmontools (http://smartmontools.sourceforge.net/); 
 > they can accurately pinpoint existing or imminent hard-disk failures.
 
I only get a handy 404 page with the above link 8^{

Jim Ford
 

Re: [linux-lvm] can't create a PV

[Jim Ford]

  
   
  > Take a look at smartmontools (http://smartmontools.sourceforge.net/);   
  > they can accurately pinpoint existing or imminent hard-disk failures.  
    
 I only get a handy 404 page with the above link 8^{  
   
 Jim Ford  
  
Just spotted the ); in the URL - ok NOW 8^} 
 
Jim Ford 
    
   

Re: [linux-lvm] can't create a PV

[Gunther Clasen]

On Mon, Feb 06, 2006, Gunther Clasen wrote:
> Hi,
> 
> I have the following problem: I have a VG which sits on two partitions.
> This VG has been created with SuSE 7.2, that is version 1 of LVM. (I
> don't know exactly which one.) I wish to extend that VG and I have tried
> to do that from SuSE 9.2, which runs
>   LVM version:     2.00.25 (2004-09-29)
>   Library version: 1.00.19-ioctl (2004-07-03)
>   Driver version:  4.1.0
> 
> The type of the partition is set to Linux LVM, like the others, but it
> does not work. I get this error:
> 
> # pvcreate -vv /dev/hdg9
>       Setting global/locking_type to 1
>       Setting global/locking_dir to /var/lock/lvm
>       File-based locking enabled.
>       Locking /var/lock/lvm/P_orphans WB
>       Getting size of /dev/hdg9
>       metadata/pvmetadatasize not found in config: defaulting to 255
>       metadata/pvmetadatacopies not found in config: defaulting to 1
>   /dev/hdg9: Couldn't find device.  Check your filters?
>       Unlocking /var/lock/lvm/P_orphans
> 
> I can't see that the filters are a problem. The entry in
> /etc/lvm/lvm.conf is:
>     filter = [ "r|/dev/.*/by-path/.*|", "r|/dev/.*/by-id/.*|", "a/.*/" ]
> 
> I understand now that I should use -M1 to add this PV to an old V1 VG,
> but that is not the problem. I still get the same error.
> 
> What am I doing wrong?

Well, I tried a few more things, thought about it, and concluded:
Nothing. I believe the program gets it wrong. The reason for this:

I had 4 partitions on my system which lvm would not detect. These were
hde9, hde10, hdg9 and hdg10. Like so:

# vgdisplay -vv vg0 | grep hde
      /dev/hde: No label detected
      /dev/hde1: No label detected
      /dev/hde3: No label detected
      /dev/hde4: No label detected
      /dev/hde5: lvm1 label detected
      /dev/hde6: lvm1 label detected
      /dev/hde7: lvm1 label detected
      /dev/hde8: lvm1 label detected

# fdisk /dev/hde
Command (m for help): p
   Device Boot      Start         End      Blocks   Id  System
/dev/hde1               1          50       25168+  83  Linux
/dev/hde2            2151      158816    78959664    5  Extended
/dev/hde3              51        1100      529200   83  Linux
/dev/hde4            1101        2150      529200   83  Linux
/dev/hde5            2151        8466     3183232+  8e  Linux LVM
/dev/hde6            8467       25216     8441968+  8e  Linux LVM
/dev/hde7           25217       58616    16833568+  8e  Linux LVM
/dev/hde8           58617       92016    16833568+  8e  Linux LVM
/dev/hde9           92017      125416    16833568+  83  Linux
/dev/hde10         125417      158816    16833568+  83  Linux

So hde9 and 10 do exist, but lvm does not even try to detect anything on
them. (No, doesn't work with partition type LVM either, I tried that.)

Partitions hdg9 and 10 did look exactly the same. I then formatted them
(hdg9/10), one with ext2, the other with reiserfs and banged them full
with data, mostly from /dev/zero, until 100% full. I then changed the
type to Linux LVM and everything works fine:

# vgdisplay -vv vg0 | grep hdg
      /dev/hdg: No label detected
      /dev/hdg1: No label detected
      /dev/hdg5: No label detected
      /dev/hdg6: No label detected
      /dev/hdg7: lvm1 label detected
      /dev/hdg8: lvm1 label detected
      /dev/hdg9: lvm2 label detected
      /dev/hdg10: No label detected

Curiously, these 4 partitions had all been used in a software-RAID
volume. So I reckon that lvm somehow picked up the metadata of the
MD-device and refused to work.

There must be some sort of bug-tracking system for lvm. Could somebody
please point me at that so that I can check this out and possibly enter
this as a bug? (Provided that the public has write access...)

Thanks!

Gunther

Re: [linux-lvm] can't create a PV

[Luca Berra]

On Tue, Feb 14, 2006 at 09:19:46AM +0000, Gunther Clasen wrote:
>
>Curiously, these 4 partitions had all been used in a software-RAID
>volume. So I reckon that lvm somehow picked up the metadata of the
>MD-device and refused to work.

this is documented in the manpage for lvm.conf

- snip -
md_component_detection (If set to 1, LVM2 will ignore devices
used as components of software RAID (md) devices by looking  for
md  superblocks. This doesn't always work satisfactorily e.g. if
a device has been  reused  without  wiping  the  md  superblocks
first.
- end snip -


-- 
Luca Berra -- bluca@comedia.it
        Communication Media & Services S.r.l.
 /"\
 \ /     ASCII RIBBON CAMPAIGN
  X        AGAINST HTML MAIL
 / \

Re: [linux-lvm] can't create a PV

[Alasdair G Kergon]

> >   LVM version:     2.00.25 (2004-09-29)
> >   Library version: 1.00.19-ioctl (2004-07-03)

Not a good version to use.
The md/partition detection was improved in 2.00.32.

Remember to run 'vgscan' after adding partitions;
and to reboot if fdisk fails to reload the partition table.

Newer versions let you add -vvvv and see exactly why any
device was ignored.  For older versions like your you
need to turn on debug logging to a file to get that information.

Alasdair
-- 
agk@redhat.com

Re: [linux-lvm] can't create a PV

[Gunther Clasen]

On Tue, Feb 14, 2006, Luca Berra wrote:

> On Tue, Feb 14, 2006 at 09:19:46AM +0000, Gunther Clasen wrote:
> >
> >Curiously, these 4 partitions had all been used in a software-RAID
> >volume. So I reckon that lvm somehow picked up the metadata of the
> >MD-device and refused to work.
> 
> this is documented in the manpage for lvm.conf
> 
> - snip -
> md_component_detection (If set to 1, LVM2 will ignore devices
> used as components of software RAID (md) devices by looking  for
> md  superblocks. This doesn't always work satisfactorily e.g. if
> a device has been  reused  without  wiping  the  md  superblocks
> first.
> - end snip -

On Tue, Feb 14, 2006, Alasdair G Kergon wrote:

> Not a good version to use.
> The md/partition detection was improved in 2.00.32.

Thank you for your help! So it is a squashed bug... ;-)

I must admit that I hadn't read man lvm.conf, although it hadn't helped:
above snip is not included in my version of it. :-(

Anyway, seems to work fine now...

Gunther

P.S.: Would have liked to use SuSE 10.0 instead of 9.2, but with support
for my modem broken, it's a non-starter :-(((