Re: [linux-lvm] [Fwd: boot from lvm volume] Is ther

Re: [linux-lvm] [Fwd: boot from lvm volume] Is ther

[Michael Marxmeier]

Forwarded message from Rolf Jakob (rjakob@duffy1.franken.de) ...

-------- Original Message --------
Message-Id: <m13CqwY-0001aXC@duffy1.franken.de>
Subject: Re: [linux-lvm] [Fwd: boot from lvm volume] Is ther
In-Reply-To: <396B8B3D.88BD3F73@libertysurf.fr> from =?iso-8859-1?Q?PhilippeLef=E8vre?= at "Jul 11, 2000  5: 1:49 pm"
To: ph.l@libertysurf.fr (=?iso-8859-1?Q?PhilippeLef=E8vre?=)
Date: Thu, 13 Jul 2000 23:52:41 +0200 (MEST)
Sender: rjakob@duffy1.franken.de

Hello,

> I understood that you use the initrd way to getting up your first VG but before
> that, how can you do to put /var /usr /sbin etc... under LVM. I mean, changing
> the filesystem tag (-> 0x8e) then creating PV, VG and LVs will distroy all
> datas on disk !!
Correct. I don't have a click'n'go solution. Once I migrated an existing
conventionally installed system to LVM by simply using another partition as a
PV, put everything I needed into LVs, made sure it will boot using initrd
and finally added the first old partition as another PV. So I ended up with
two PVs on one physical disk. I wouldn't really recommend that way over a clean
installation but it works.

> Is there any way to create LVs before installing my RH distribution ?
That's the preferred way. I have a collection of all necessary packages, so I
don't use one of the available distributions and can only tell you the basics.
You need a boot disk with an lvm enabled kernel (compiled in or module) and
you need access to the disk before your installation routine starts installing
packages. I don't know about the RH install procedure so you have to try on
your own. What I do to install a lvm system, is :
Boot a kernel from floppy and read a ramdisk image from a second floppy.
In this ramdisk I put all the necessary tools to create partitions (fdisk),
set up lvm (modprobe,lvm.o, vgscan, vgchange, pvcreate, etc.). Then the work
starts as I don't have a handy install script for that. I create two partitions,
one small one for the kernel, ramdisk and the lilo files and one that will
become my PV. In the VG I create all the LVs and filesystems I want to have
and mount the root LV under /newroot, usr LV under /newroot/usr and so on.
Then I start my very simple install script that will setup a small system
in /newroot. The kernel, lilo configuration and what is needed plus the ramdisk
is put on the small partition and lilo gets installed. After that the system
is ready to boot and more packages get installed.
So you see, if you want to have your RH system installed in a similar way
you need a possibility to create the VG, LVs and the file systems and then
return to the setup program and install in the prepared place.
I use ext2prepare on each file system and leave some space free for future
resizes.

> NB: LVM is integrated into my kernel and is not a module.
You have to use an initrd anyway, so the integration just saves the
modprobe lvm. I have that in my linuxrc of the ramdisk.

Rolf
-- 
Rolf Jakob at home (rjakob@duffy1.franken.de)
WWW : http://www.franken.de/users/duffy1/rjakob (KDE-Utils and CCS)

Re: [linux-lvm] [Fwd: boot from lvm volume]

[Rolf Jakob]

Hello,

> Is it yet possible to boot from an LVM volume?
AFAIK no. I use a small partition for the kernel, an initrd image and
the lilo.conf which is later mounted as /boot.
So when the system is up the / filesystem is a logical volume and can
be resized online like all the other filesystems I use.
Lilo boots the kernel from that partition, loads an initial ramdisk
and executes the linuxrc script. In this script the needed modules are
loaded (ide.o or the SCSI modules and the lvm module), the volume group
is activated and by writing the major/minor number of the boot logical
volume ( I use the first logical volume as the root LV ) to
/proc/sys/kernel/real-root-dev the kernel will mount that one as the
new root filesystem.
I use that for five different systems now. My plannings were to use the
boot partition as a rescue system as well but I did it only on one
system (proof of concept, but I found out that rescue floppies are enough
for me).

> I like also mirrored / .
Hmm, that would mean that the master boot record should be mirrored as well,
otherwise you would loose your installed lilo. I haven't tried that yet.

Rolf
-- 
Rolf Jakob at home (rjakob@duffy1.franken.de)
WWW : http://www.franken.de/users/duffy1/rjakob (KDE-Utils and CCS)

Re: [linux-lvm] [Fwd: boot from lvm volume] Is ther

[Philippe Lefèvre]

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Hello,

I'm very interested in using LVM for the root partitions (I use Redhat 6.2) as
I can do with IBM AIX.

I would like to make a rootvg containing some LVs with /var /tmp /bin /usr
/home for example, then make a datavg for SGBD, datas and so on.

As I plan to update my production system running 2.2.16 to 2.4.0 as soon this
new kernel is available, I did some tests with the new kernel-2.4.0.test2 and
lvm-0.8final patched. It seems to work perfectly but I was unable to find a way
to put rootvg under LVM.

I understood that you use the initrd way to getting up your first VG but before
that, how can you do to put /var /usr /sbin etc... under LVM. I mean, changing
the filesystem tag (-> 0x8e) then creating PV, VG and LVs will distroy all
datas on disk !!

Is there any way to create LVs before installing my RH distribution ?

Did I missed something ? Is there any documentation that could explain how to
do this ?


NB: LVM is integrated into my kernel and is not a module.


Could you please help me on that subject ?

Thank you in advance,

PhiL


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