[linux-lvm] Problem creating snapshots with 2.6.16.9 and LVM 2.02.06

[linux-lvm] Problem creating snapshots with 2.6.16.9 and LVM 2.02.06

[Roger Lucas]

Hi,

I am running what was Debian Sarge but has the new 2.6.16.9 kernel.  I have
made a few patches to the kernel (to add an Areca RAID driver and a few
hardware sensors) but nothing in the device-mapper areas.  I use the
snapshots capability in LVM to snapshot the client's userdisk volume when
backing it up.

Until a couple days ago, I was running:

Wombat:~# uname -a
Linux Wombat 2.6.16.9.rwl7 #1 Tue May 16 20:25:14 BST 2006 i686 GNU/Linux
Wombat:~# lvm version
  LVM version:     2.01.04 (2005-02-09)
  Library version: 1.01.00-ioctl (2005-01-17)
  Driver version:  4.4.0
Wombat:~#

and everything ran fine.

A few days ago, I saw an e-mail from Alasdair on this mailing list saying
that kernels 2.6.16 onwards should be using the later userspace tools.
Following this, I downloaded and compiled the latest device mapper library
(libdevmapper 1.02) and LVM tools (2.02.06).  When I installed them on the
machine and re-ran the backup script, I got an error from lvcreate when I
tried to make the snapshot which I did not get before.  I saw that Patrick
Honing also reported this error on 29/5/06 on this mailing list, but
couldn't see any reply.

For me, this failure is 100% repeatable.

Can anyone help shed light on this?

If you need any more information then please let me know and I will send it
in.  My current option seems to be to drop back to the older 2.01.04 lvm and
1.01 dmapper but given Alasdair's mail, this seems to be risky.

The full shell trace is below.

Wombat:~# uname -a
Linux Wombat 2.6.16.9.rwl7 #1 Tue May 16 20:25:14 BST 2006 i686 GNU/Linux
Wombat:~# lvm version
  LVM version:     2.02.06 (2006-05-12)
  Library version: 1.02.07 (2006-05-11)
  Driver version:  4.5.0
Wombat:~# lvs
  LV          VG          Attr   LSize  Origin Snap%  Move Log Copy%
  backupimage clientstore -ri-ao 60.00G
  root        clientstore -wi-ao  5.00G
  userdisk    clientstore -wi-ao 60.00G
Wombat:~# vgs
  VG          #PV #LV #SN Attr   VSize   VFree
  clientstore   1   3   0 wz--n- 148.98G 23.98G
Wombat:~# pvs
  PV         VG          Fmt  Attr PSize   PFree
  /dev/sda2  clientstore lvm2 a-   148.98G 23.98G
Wombat:~# lvcreate -L10G -n snapdisk -s /dev/clientstore/userdisk
  LV clientstore/snapdisk in use: not deactivating
  Couldn't deactivate new snapshot.
Wombat:~# lvs
  LV          VG          Attr   LSize  Origin Snap%  Move Log Copy%
  backupimage clientstore -ri-ao 60.00G
  root        clientstore -wi-ao  5.00G
  snapdisk    clientstore -wi-a- 10.00G
  userdisk    clientstore -wi-ao 60.00G
Wombat:~#


Many thanks in advance,

Roger

RE: [linux-lvm] Problem creating snapshots with 2.6.16.9 and LVM 2.02.06

[Roger Lucas]

As a follow up, I have also tried it with the 2.6.16.20 kernel which is
fresh from kernel.org.  Same problem.

> -----Original Message-----
> From: linux-lvm-bounces@redhat.com [mailto:linux-lvm-bounces@redhat.com]
> On Behalf Of Roger Lucas
> Sent: 09 June 2006 14:43
> To: 'LVM general discussion and development'
> Subject: [linux-lvm] Problem creating snapshots with 2.6.16.9 and LVM
> 2.02.06
> 
> Hi,
> 
> I am running what was Debian Sarge but has the new 2.6.16.9 kernel.  I
> have
> made a few patches to the kernel (to add an Areca RAID driver and a few
> hardware sensors) but nothing in the device-mapper areas.  I use the
> snapshots capability in LVM to snapshot the client's userdisk volume when
> backing it up.
> 
> Until a couple days ago, I was running:
> 
> Wombat:~# uname -a
> Linux Wombat 2.6.16.9.rwl7 #1 Tue May 16 20:25:14 BST 2006 i686 GNU/Linux
> Wombat:~# lvm version
>   LVM version:     2.01.04 (2005-02-09)
>   Library version: 1.01.00-ioctl (2005-01-17)
>   Driver version:  4.4.0
> Wombat:~#
> 
> and everything ran fine.
> 
> A few days ago, I saw an e-mail from Alasdair on this mailing list saying
> that kernels 2.6.16 onwards should be using the later userspace tools.
> Following this, I downloaded and compiled the latest device mapper library
> (libdevmapper 1.02) and LVM tools (2.02.06).  When I installed them on the
> machine and re-ran the backup script, I got an error from lvcreate when I
> tried to make the snapshot which I did not get before.  I saw that Patrick
> Honing also reported this error on 29/5/06 on this mailing list, but
> couldn't see any reply.
> 
> For me, this failure is 100% repeatable.
> 
> Can anyone help shed light on this?
> 
> If you need any more information then please let me know and I will send
> it
> in.  My current option seems to be to drop back to the older 2.01.04 lvm
> and
> 1.01 dmapper but given Alasdair's mail, this seems to be risky.
> 
> The full shell trace is below.
> 
> Wombat:~# uname -a
> Linux Wombat 2.6.16.9.rwl7 #1 Tue May 16 20:25:14 BST 2006 i686 GNU/Linux
> Wombat:~# lvm version
>   LVM version:     2.02.06 (2006-05-12)
>   Library version: 1.02.07 (2006-05-11)
>   Driver version:  4.5.0
> Wombat:~# lvs
>   LV          VG          Attr   LSize  Origin Snap%  Move Log Copy%
>   backupimage clientstore -ri-ao 60.00G
>   root        clientstore -wi-ao  5.00G
>   userdisk    clientstore -wi-ao 60.00G
> Wombat:~# vgs
>   VG          #PV #LV #SN Attr   VSize   VFree
>   clientstore   1   3   0 wz--n- 148.98G 23.98G
> Wombat:~# pvs
>   PV         VG          Fmt  Attr PSize   PFree
>   /dev/sda2  clientstore lvm2 a-   148.98G 23.98G
> Wombat:~# lvcreate -L10G -n snapdisk -s /dev/clientstore/userdisk
>   LV clientstore/snapdisk in use: not deactivating
>   Couldn't deactivate new snapshot.
> Wombat:~# lvs
>   LV          VG          Attr   LSize  Origin Snap%  Move Log Copy%
>   backupimage clientstore -ri-ao 60.00G
>   root        clientstore -wi-ao  5.00G
>   snapdisk    clientstore -wi-a- 10.00G
>   userdisk    clientstore -wi-ao 60.00G
> Wombat:~#
> 
> 
> Many thanks in advance,
> 
> Roger
> 
> _______________________________________________
> linux-lvm mailing list
> linux-lvm@redhat.com
> https://www.redhat.com/mailman/listinfo/linux-lvm
> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/

Re: [linux-lvm] Problem creating snapshots with 2.6.16.9 and LVM 2.02.06

[Alasdair G Kergon]

> > Wombat:~# lvcreate -L10G -n snapdisk -s /dev/clientstore/userdisk
> >   LV clientstore/snapdisk in use: not deactivating
> >   Couldn't deactivate new snapshot.

Could be interaction (not yet understood) with udev - try disabling udev while
running the command.

(Ref debian bug 343671)

Alasdair
-- 
agk@redhat.com

RE: [linux-lvm] Problem creating snapshots with 2.6.16.9 and LVM2.02.06

[Roger Lucas]

Hi Alasdair,

Thanks for the quick response.

I killed the uDev process that was running and retried it.  The snapshot was
created without any problems.  It looks like this is another example of the
interaction of uDev and LVM.

I followed the Debian bug reference that you gave.  The change in
/etc/udev.rules that was recommended works for me too:

Failing line:
	KERNEL=="dm-[0-9]*",           NAME=""

Working line:
	KERNEL=="dm-[0-9]*",           OPTIONS+="ignore_device"

This seems to keep uDev out of LVM's way, and LVM now works fine.

There seemed to a bit of discussion on the Debian bug tracker regarding
exactly where the problem is, so if there are any logs you would like or
similar then let me know.

Thanks and best regards,

Roger


> -----Original Message-----
> From: linux-lvm-bounces@redhat.com [mailto:linux-lvm-bounces@redhat.com]
> On Behalf Of Alasdair G Kergon
> Sent: 09 June 2006 15:57
> To: LVM general discussion and development
> Subject: Re: [linux-lvm] Problem creating snapshots with 2.6.16.9 and
> LVM2.02.06
> 
> > > Wombat:~# lvcreate -L10G -n snapdisk -s /dev/clientstore/userdisk
> > >   LV clientstore/snapdisk in use: not deactivating
> > >   Couldn't deactivate new snapshot.
> 
> Could be interaction (not yet understood) with udev - try disabling udev
> while
> running the command.
> 
> (Ref debian bug 343671)
> 
> Alasdair
> --
> agk@redhat.com
> 
> _______________________________________________
> linux-lvm mailing list
> linux-lvm@redhat.com
> https://www.redhat.com/mailman/listinfo/linux-lvm
> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/