Re: [linux-lvm] Rescue cd for lvm 1.0.3 (fwd)

Re: [linux-lvm] Rescue cd for lvm 1.0.3 (fwd)

[Thorsten Sauter]

Hello all,

again a little question. i have currently the following configuration:

# fdisk -l /dev/hda
/dev/hda1	1	1115		8e Linux LVM

/dev/hda1 => rootvg

rootvg
   /dev/rootvg/root		/
   /dev/rootvg/usr		/usr
   /dev/rootvg/boot             /boot

Why this configuration is so bad? Is it better to leave the /boot on an
"normal" ext2 filesystem? But, what files need the kernel from /boot to
bootup the system correctly? I think the kernel will be stored in the
master boot record with lilo?
And all files from /boot are accessable, after the ramdisk was loaded.

Btw. linux boot up succesfull, on my other system, where the /boot is on
an logival volume.

Any hints?

Thx
Thorsten

---------- Forwarded message ----------
Date: Tue, 26 Feb 2002 11:08:16 -0000
From: William Blunn <bill@tao-group.com>
Reply-To: linux-lvm@sistina.com
To: linux-lvm@sistina.com
Subject: Re: [linux-lvm] Rescue cd for lvm 1.0.3

> not really a lvm problem, but after moving my system to boot from an
> root-lvm, my lilo stops with the LI error. I think, rewriting the lilo
> could help, but how can I access my system datas?

"boot from an root-lvm" ... sounds dodgy to me.

You can have the *root* filesystem "/" on an LVM volume.

However the *boot* filesystem should be /boot, which should be a small
ext2 partition mounted directly on a partition.

Bill
-- 
William H. Blunn - bill+linuxlvm@tao-group.com
Tao
62/63 Suttons Business Park, Earley, READING, RG6 1AZ, United Kingdom
Tel: +44 118 901 2999 - Fax: +44 118 901 2963 - http://tao-group.com/


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Re: [linux-lvm] Rescue cd for lvm 1.0.3 (fwd)

[Remco Post]

Because lilo doesn't have a clue about lvm, so it cannot properly store the 
location of your kernel in your boot record if /boot is also in lvm (like in 
your setup). That is why the lvm howto tells you you must have /boot on a 
separate (dos) partition (eg hda1).

> 
> 
> Hello all,
> 
> again a little question. i have currently the following configuration:
> 
> # fdisk -l /dev/hda
> /dev/hda1	1	1115		8e Linux LVM
> 
> /dev/hda1 => rootvg
> 
> rootvg
>    /dev/rootvg/root		/
>    /dev/rootvg/usr		/usr
>    /dev/rootvg/boot             /boot
> 
> Why this configuration is so bad? Is it better to leave the /boot on an
> "normal" ext2 filesystem? But, what files need the kernel from /boot to
> bootup the system correctly? I think the kernel will be stored in the
> master boot record with lilo?
> And all files from /boot are accessable, after the ramdisk was loaded.
> 
> Btw. linux boot up succesfull, on my other system, where the /boot is on
> an logival volume.
> 
> Any hints?
> 
> Thx
> Thorsten
> 
> ---------- Forwarded message ----------
> Date: Tue, 26 Feb 2002 11:08:16 -0000
> From: William Blunn <bill@tao-group.com>
> Reply-To: linux-lvm@sistina.com
> To: linux-lvm@sistina.com
> Subject: Re: [linux-lvm] Rescue cd for lvm 1.0.3
> 
> > not really a lvm problem, but after moving my system to boot from an
> > root-lvm, my lilo stops with the LI error. I think, rewriting the lilo
> > could help, but how can I access my system datas?
> 
> "boot from an root-lvm" ... sounds dodgy to me.
> 
> You can have the *root* filesystem "/" on an LVM volume.
> 
> However the *boot* filesystem should be /boot, which should be a small
> ext2 partition mounted directly on a partition.
> 
> Bill
> -- 
> William H. Blunn - bill+linuxlvm@tao-group.com
> Tao
> 62/63 Suttons Business Park, Earley, READING, RG6 1AZ, United Kingdom
> Tel: +44 118 901 2999 - Fax: +44 118 901 2963 - http://tao-group.com/
> 
> 
> _______________________________________________
> 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
> 
> 
> _______________________________________________
> 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
> 

-- 
Met vriendelijke groeten,

Remco Post

SARA - Stichting Academisch Rekencentrum Amsterdam
High Performance Computing  Tel. +31 20 592 8008    Fax. +31 20 668 3167

"I really didn't foresee the Internet. But then, neither did the computer
industry. Not that that tells us very much of course - the computer industry
didn't even foresee that the century was going to end." -- Douglas Adams

Re: [linux-lvm] Rescue cd for lvm 1.0.3 (fwd)

[Andreas Dilger]

On Feb 26, 2002  13:27 +0100, Thorsten Sauter wrote:
> again a little question. i have currently the following configuration:
> 
> # fdisk -l /dev/hda
> /dev/hda1	1	1115		8e Linux LVM
> 
> /dev/hda1 => rootvg
> 
> rootvg
>    /dev/rootvg/root		/
>    /dev/rootvg/usr		/usr
>    /dev/rootvg/boot             /boot
> 
> Why this configuration is so bad? Is it better to leave the /boot on an
> "normal" ext2 filesystem? But, what files need the kernel from /boot to
> bootup the system correctly? I think the kernel will be stored in the
> master boot record with lilo?

Actually, if you use LILO it doesn't need to understand anything about LVM
in order to boot.  LILO 22.1 (or a patched LILO 21.6+) will talk with the
LVM driver to map out the blocks for the kernel and initrd into the MBR,
so that when you are booting it just reads the blocks by number.

Some possible problems include the fact that /boot may be too far from the
start of the disk and older BIOSes have problems with kernel/initrd over
cylinder 1024.  Also, you need to run LILO _every_ time you update your
kernel and initrd, because it has to re-map all of the blocks into the
MBR.

The real danger is having your / partition in LVM, because if there is
ever a problem with your LVM configuration then you cannot access the
right tools, and also your LVM config backups are inaccessible.

Cheers, Andreas
--
Andreas Dilger
http://sourceforge.net/projects/ext2resize/
http://www-mddsp.enel.ucalgary.ca/People/adilger/

RE: [linux-lvm] Rescue cd for lvm 1.0.3 (fwd)

[Yves Alloyer]

> -----Original Message-----
> From: linux-lvm-admin@sistina.com [mailto:linux-lvm-admin@sistina.com]On
> Behalf Of Remco Post
> Sent: Tuesday, February 26, 2002 1:53 PM
> To: linux-lvm@sistina.com
> Subject: Re: [linux-lvm] Rescue cd for lvm 1.0.3 (fwd)
>
>
>
> Because lilo doesn't have a clue about lvm, so it cannot properly
> store the
> location of your kernel in your boot record if /boot is also in
> lvm (like in
> your setup). That is why the lvm howto tells you you must have /boot on a
> separate (dos) partition (eg hda1).
IMHO this only applies to stock lilo as found in most current and all older
distros.
I have a recent and patched version of lilo that does recognize LVM.
My vgroot (with /, /var /tmp, /boot, etc.) is in LVM. It's all reiserfs.
It's
running over software raid (mirroring of course).
Works like a charm. As a special measure, though I don't know if I still
need that (anybody?),
I take care of having /boot and / in low numbered PEs.
Works like a charm so far... many thanks to you guys out there.
<OT>I also have autofs, nisplus (client). The result is a box with an easy
to
administer enterprise grade OS. Just love it.</OT>

(snip...)
> --
> Met vriendelijke groeten,
>
> Remco Post
>
> SARA - Stichting Academisch Rekencentrum Amsterdam
> High Performance Computing  Tel. +31 20 592 8008    Fax. +31 20 668 3167
>
> "I really didn't foresee the Internet. But then, neither did the computer
> industry. Not that that tells us very much of course - the
> computer industry
> didn't even foresee that the century was going to end." -- Douglas Adams
>
>
>
> _______________________________________________
> 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
>

Best regards,
Yves

Re: [linux-lvm] Rescue cd for lvm 1.0.3 (fwd)

[William Blunn]

> > Because lilo doesn't have a clue about lvm, so it cannot properly
> > store the location of your kernel in your boot record if /boot is
> > also in lvm (like in your setup). That is why the lvm howto tells
> > you you must have /boot on a separate (dos) partition (eg hda1).

> IMHO this only applies to stock lilo as found in most current and 
> all older distros.
> I have a recent and patched version of lilo that does recognize LVM.

For the sake of 8MB of disk, I'd be inclined to go with the /boot on an
ext2 filesystem directly on a disk partition.

That way you will be compatible with the stock lilo, which will:

(a) Save you building your own lilo. Yes I know it is easy, but it's not
    just the the direct time involved in doing it (which probably
    outweighs 8MB of disk by itself anyway). You also have the ongoing
    system management effort in having to manage (another) one of your
    components no longer being the out-of-the-box distro version.

(b) Save you grief in the event that the boot setup on your system
    fails, as you can potentially the stock lilo.

Over time, as new versions of distros appear containing new versions of
lilo, and systems are upgraded to newer distro versions, then the
prevalent population of lilo instances will eventually become LVM-aware.

Regards,

Bill
-- 
William H. Blunn - <bill+s.20020227@tao-group.com> - Developer Support
Tao
62/63 Suttons Business Park, Earley, READING, RG6 1AZ, United Kingdom
Tel: +44 118 901 2999 - Fax: +44 118 901 2963 - http://tao-group.com/