[linux-lvm] is devfs required?

[linux-lvm] is devfs required?

[Vincent AE Scott]

Hi there,
i've been tinkering with LVM, but i'm having some issues with it, and i
was wondering if anyone here could help shed some light for me?

i'm using LVM on a 2.4.17-19mdk kernel patched up to 1.0.3
it *appears* that when i boot up without devfs support, i frequently
cant create/extened/mount filesystems.  but when i boot up with devfs
support it seems to work.

is devfs required to use LVM?

without it, ive seen lvcreate SEGV when attempting to create a new
volume.  

or are there any known problems with using LVM on an SMP host?  i cant
think of anything else that might be causing these strange problems.

oh, and FYI, it was setup up using 1.0.1-rc4ish

TIA,
-vince

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 Smash forehead on keyboard to continue... 

Re: [linux-lvm] is devfs required?

[Heinz J . Mauelshagen]

On Thu, Feb 21, 2002 at 02:36:02PM +0000, Vincent AE Scott wrote:
> Hi there,
> i've been tinkering with LVM, but i'm having some issues with it, and i
> was wondering if anyone here could help shed some light for me?
> 
> i'm using LVM on a 2.4.17-19mdk kernel patched up to 1.0.3
> it *appears* that when i boot up without devfs support, i frequently
> cant create/extened/mount filesystems.  but when i boot up with devfs
> support it seems to work.
> 
> is devfs required to use LVM?

No, but in case you use devfs, you need to go with the long devfs
device pathes.

> 
> without it, ive seen lvcreate SEGV when attempting to create a new
> volume.  

Hm.
Seems to be more of a tool bug.
Which tool version are you using?
In case of 0.9.1 Beta something, you should update to 1.0.3, which we
released last Monday.

> 
> or are there any known problems with using LVM on an SMP host?  i cant
> think of anything else that might be causing these strange problems.
> 
> oh, and FYI, it was setup up using 1.0.1-rc4ish

That should be fine but as said, you could still run older tools
which might be causing the SEGV.

> 
> TIA,
> -vince
> 
> -- 
> PGP key:  http://codex.net/pgp/pgp.asc
> 
>  Smash forehead on keyboard to continue... 
> 
> 
> _______________________________________________
> linux-lvm mailing list
> linux-lvm@sistina.com
> http://lists.sistina.com/mailman/listinfo/linux-lvm
> read the LVM HOW-TO at http://www.sistina.com/lvm/Pages/howto.html

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Heinz    -- The LVM Guy --

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    Nevertheless it needs not so stupid people to solve them ***

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Re: [linux-lvm] is devfs required?

[Benjamin Scott]

> or are there any known problems with using LVM on an SMP host?

  We're using LVM 1.0 on kernel 2.2.20 with SMP and without devfs just fine.

> without it, ive seen lvcreate SEGV when attempting to create a new
> volume.  
[...]
> i cant think of anything else that might be causing these strange
> problems.

   I notice from your kernel version (2.4.17-19mdk) that you are using
Mandrake.  Try compiling from pristine sources.  Who knows what Mandrake has
done to their kernel or tools?

  Also, Mandrake uses Red Hat's goofy "GCC 2.96" compiler by default.  Try
using "kgcc" to compile your kernel and LVM tools instead.  Red Hat's
compiler is notorious for causing weird problems.

-- 
Ben Scott <bscott@ntisys.com>
| The opinions expressed in this message are those of the author and do not |
| necessarily represent the views or policy of any other person, entity or  |
| organization.  All information is provided without warranty of any kind.  |

Re: [linux-lvm] is devfs required?

[Luca Berra]

On Fri, Feb 22, 2002 at 09:22:03AM -0500, Benjamin Scott wrote:
>    I notice from your kernel version (2.4.17-19mdk) that you are using
> Mandrake.  Try compiling from pristine sources.  Who knows what Mandrake has
> done to their kernel or tools?
whoever whishes to look at their SRPMS :)))
anyway i added lvm to mandrake kernels and it works ok.

>   Also, Mandrake uses Red Hat's goofy "GCC 2.96" compiler by default.  Try
> using "kgcc" to compile your kernel and LVM tools instead.  Red Hat's
> compiler is notorious for causing weird problems.
mandrake gcc 2.96 is known to work with lvm while redhat one is not.

L.


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Luca Berra -- bluca@comedia.it
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Re: [linux-lvm] is devfs required?

[Luca Berra]

On Thu, Feb 21, 2002 at 02:36:02PM +0000, Vincent AE Scott wrote:
> i'm using LVM on a 2.4.17-19mdk kernel patched up to 1.0.3
> it *appears* that when i boot up without devfs support, i frequently
> cant create/extened/mount filesystems.  but when i boot up with devfs
> support it seems to work.
> 
> is devfs required to use LVM?
i am also using 2.4.17-19mdk + LVM
the issue is not with the kernel portion but with the tools portion
if you start using lvm with devfs you are stuck with it and vice-versa.
i proposed a workaround about 13 months ago, but never actually got
to code it. :(

> without it, ive seen lvcreate SEGV when attempting to create a new
> volume.  
which version of the tools are u using?
if it is current can you provide a debug output?
if you want to build an rpm for recent tools fetch spec and
patch from http://www.comedia.it/bluca/lvm and adapt it
to 1.0.3 (will upgrade the site soon)
the mkinitrd stuff does not work with 2.4.17-19mdk and xfs

> or are there any known problems with using LVM on an SMP host?  i cant
> think of anything else that might be causing these strange problems.
no known issues.

L.


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Re: [linux-lvm] is devfs required?

[Vincent AE Scott]

Luca Berra(bluca@comedia.it)@Fri, Feb 22, 2002 at 09:12:51PM +0100:
> On Thu, Feb 21, 2002 at 02:36:02PM +0000, Vincent AE Scott wrote:
> > i'm using LVM on a 2.4.17-19mdk kernel patched up to 1.0.3
> > it *appears* that when i boot up without devfs support, i frequently
> > cant create/extened/mount filesystems.  but when i boot up with devfs
> > support it seems to work.
> > 
> > is devfs required to use LVM?
> i am also using 2.4.17-19mdk + LVM
> the issue is not with the kernel portion but with the tools portion
> if you start using lvm with devfs you are stuck with it and vice-versa.
> i proposed a workaround about 13 months ago, but never actually got
> to code it. :(

errr, are you saying that it's not possible to switch between devfs and
non-devfs, as soon as you use the former?

i thought i'd actually done exactly that, i.e. rebooted without devfs
mounted.  but i could be wrong.


 
> > without it, ive seen lvcreate SEGV when attempting to create a new
> > volume.  
> which version of the tools are u using?

i started off with 1.0.1-rc4ish, which came from lvm-1.0.1-1mdk.
but since then, i've upgraded kernel+tools to 1.0.3


> if it is current can you provide a debug output?


alas, not anymore, but i did strace the binaries a few times.
each time it looked like they were enumerating devices on the system,
going thru ide devices, and then loopback ones.  it was when going thru
the loopback devices that it consistantly crashed.  each time it was the
same one, loop8 IIRC.  altho, i think it was probably more todo with
going thru a certain *number* of devices.

i did build debug binaries, and again, IIRC, i think the SEGV was in
either:

	vg_status_with_pv_and_lv.c
or	vg_setup_pointers_for_snapshots.c


if it sounds like something which has already been fixed, then please
ignore me.  but if it's not, then i can always revert the
binaries/kernel and provide more in depth information.


> if you want to build an rpm for recent tools fetch spec and
> patch from http://www.comedia.it/bluca/lvm and adapt it
> to 1.0.3 (will upgrade the site soon)
> the mkinitrd stuff does not work with 2.4.17-19mdk and xfs

ahh, not a problem, i'm not using xfs for anything apart from testing,
as it doesnt appear to be that stable - for me anyway.


> 
> > or are there any known problems with using LVM on an SMP host?  i cant
> > think of anything else that might be causing these strange problems.
> no known issues.


oh, i've just thought of one other thing, that maybe? caused a problem:
i did create a LV and copied my entire /fs into it, then rebooted into
it to see if it all worked.  havent used it since tho.

is it possible that the data in /etc/lvm* on the original and LVM copied
partitions were not quite in sync with what was on disk?


regards,
-vince

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Re: [linux-lvm] is devfs required?

[Luca Berra]

On Fri, Feb 22, 2002 at 09:40:37PM +0000, Vincent AE Scott wrote:
> errr, are you saying that it's not possible to switch between devfs and
> non-devfs, as soon as you use the former?
well, the issue is that the lvm device cache does not cope with
variyng device names, as happens when using devfs (i.e. you have both
/dev/scsi/host0/bus0/target0/lun0/part1
and
/dev/sda1
to reference the same partitin

the worst case is when you have devfs compiled in and not mounted,
so /proc/partitions holds the long device name, but /dev contains
only the short one.

> oh, i've just thought of one other thing, that maybe? caused a problem:
> i did create a LV and copied my entire /fs into it, then rebooted into
> it to see if it all worked.  havent used it since tho.
> 
> is it possible that the data in /etc/lvm* on the original and LVM copied
> partitions were not quite in sync with what was on disk?

the data in /etc/lvmtab.d can be recreated by using vgscan
that in /etc/lvmconf by vgcfgbackup

L.

-- 
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