topic Re: fedora lvm root disk .... in Operating System - Linux

fedora lvm root disk ....

K.C. Chan — Tue, 09 Aug 2005 19:33:58 GMT

all,
I am running fedora3, I am trying to get lvm on root partition to work. However I need to add the lvm module to initrd. I tried including dm_mod in the initrd creation process, but could not locate it. Does any one know what module I should add to the initrd process in order to support lvm on root partition? Thanks.

Re: fedora lvm root disk ....

Steven Chan_9 — Wed, 10 Aug 2005 01:25:28 GMT

Hi~

Did you use mkinitrd to create ram disk?

If you used mkinitd, try:

mkinitrd -v --preload dm-mod image-name `uname -r`

regards,
Steven Chan

Re: fedora lvm root disk ....

Stuart Browne — Wed, 10 Aug 2005 04:31:58 GMT

Do you have your kernels on your /root filesystem, or on a separate (non-lvm) /boot filesysetm?

Re: fedora lvm root disk ....

K.C. Chan — Wed, 10 Aug 2005 08:46:04 GMT

Yeah, I have a separate boot, that works find. Kernel and initrd resides there. I added the dm_mod module, but still getting kernel panic.

error:
mkrootdev: label /root not found
mounting root filesystem
mount: error 2 mounting ext3
mount: error 2 mounting none
Switching to new root
switchroot: mount failed: 22
umount /initrd/dev failed: 2
Kernel panic - not syncing: Attempted to kill init!

this part with /root label is the the root partition underl lvm, I migrated it from the original root partition (/dev/hda2) which I did not wipe out. If I boot using /dev/hda2 I am back where I started. Is there anything I need to do to get mkrootdev to work with the new lvm root partition labeled: /root? Thanks.

Re: fedora lvm root disk ....

Steven Chan_9 — Wed, 10 Aug 2005 09:42:03 GMT

Hi~

What is your lvm root file system labeled?

If not, use tune2fs -L to change your lvm root file system's label.

And do not connect 2 partition with the same label one system together.

regards,
Steven Chan

Re: fedora lvm root disk ....

K.C. Chan — Wed, 10 Aug 2005 09:48:00 GMT

the old label is "/" and the new label is "/root". I think the problem is that it is having issue with the new root file system because it is under lvm2. I thought loading the dm_mod module would help. But in retrospect, you would have to activate the volume by running vgscan first; hence mkroot dev can't find the new root filesystem (which is under lvm2). Any idea how to get around this?

Re: fedora lvm root disk ....

Steven Chan_9 — Wed, 10 Aug 2005 10:00:52 GMT

Hi~

I had tryed to mkinitrd with dm-mod preloaded under RHEL4, mkinitrd will include lvm2 into ram disk automatically. But I have not try this on FC3.

What is you mkinitrd version? maybe your mkinitrd is too old to support lvm2.

BTW, the module name on kernel tree of dm_mod is dm-mod.

regards
Steven Chan

Re: fedora lvm root disk ....

K.C. Chan — Wed, 10 Aug 2005 10:04:49 GMT

the version on it is mkinitrd-4.1.18-2.

Re: fedora lvm root disk ....

Ivan Ferreira — Wed, 10 Aug 2005 10:18:17 GMT

What if you instead of using a label as a kernel option, use the device special. Like this:

kernel /vmlinuz-version ro root=/dev/VolGroup00/LogVol00

Re: fedora lvm root disk ....

K.C. Chan — Wed, 10 Aug 2005 10:20:04 GMT

Ivan, thanks for the suggestion, I already tried that.

Re: fedora lvm root disk ....

K.C. Chan — Wed, 10 Aug 2005 10:20:45 GMT

Does any one know if fedora3 support lvm for root filesystem?

Re: fedora lvm root disk ....

Steven Chan_9 — Wed, 10 Aug 2005 10:45:58 GMT

Hi~

You can boot you system via FC3 CD in rescue mode and with lvm root partition installed. If rescue mode can detect you root file system on lvm and mounted, chroot to the mounted root file system then mkinitrd again.

Maybe this will make mkinitrd to include lvm2 into ram disk.

regards,
Steven Chan

Re: fedora lvm root disk ....

Steven Chan_9 — Wed, 10 Aug 2005 10:48:56 GMT

Hi~

FC3 suppor root file system on LVM.

I did it long time ago, but I did it during the OS installation with Disk Druid.

regards
Steven Chan

Re: fedora lvm root disk ....

K.C. Chan — Wed, 10 Aug 2005 11:09:18 GMT

This is what I got when creatig initrd with mkinitrd:
Creating initramfs
Looking for deps of module dm-mod
Looking for deps of module ide-disk
Looking for deps of module dm-mod
Looking for deps of module ext3 jbd
Looking for deps of module jbd
Looking for deps of module xfs
Using modules: ./kernel/drivers/md/dm-mod.ko ./kernel/fs/jbd/jbd.ko ./kernel/fs/ext3/ext3.ko ./kernel/fs/xfs/xfs.ko
/sbin/nash -> /tmp/initrd.FQ5577/bin/nash
/sbin/insmod.static -> /tmp/initrd.FQ5577/bin/insmod
/sbin/udev.static -> /tmp/initrd.FQ5577/sbin/udev
/etc/udev/udev.conf -> /tmp/initrd.FQ5577/etc/udev/udev.conf
copy from /lib/modules/2.6.10-1.770_FC3smp/./kernel/drivers/md/dm-mod.ko(elf32-i386) to /tmp/initrd.FQ5577/lib/dm-mod.ko(elf32-i386)
copy from /lib/modules/2.6.10-1.770_FC3smp/./kernel/fs/jbd/jbd.ko(elf32-i386) to /tmp/initrd.FQ5577/lib/jbd.ko(elf32-i386)
copy from /lib/modules/2.6.10-1.770_FC3smp/./kernel/fs/ext3/ext3.ko(elf32-i386) to /tmp/initrd.FQ5577/lib/ext3.ko(elf32-i386)
copy from /lib/modules/2.6.10-1.770_FC3smp/./kernel/fs/xfs/xfs.ko(elf32-i386) to /tmp/initrd.FQ5577/lib/xfs.ko(elf32-i386)
Loading module dm-mod
Loading module jbd
Loading module ext3
Loading module xfs

I do not see lvm? am I missing something?

Re: fedora lvm root disk ....

K.C. Chan — Wed, 10 Aug 2005 11:15:35 GMT

Steven,
chrooting still not working. Same error? does any one know else should be included in initrd inorder to support lvm on root?

Re: fedora lvm root disk ....

Steven Chan_9 — Thu, 11 Aug 2005 09:52:56 GMT

Hi KC,

I think you have to create initrd manunally.

The following modules have to be inculded:

dm-mirror.ko
dm-mod.ko
dm-snapshot.ko
dm-zero.ko
ext3.ko
jbd.ko

/usr/sbin/lvm.static has to be copied to initrd's /bin/lvm, and /etc/lvm/lvm.conf should be included also.

And here is a sample of init script on initrd:

#!/bin/nash

mount -t proc /proc /proc
setquiet
echo Mounted /proc filesystem
echo Mounting sysfs
mount -t sysfs none /sys
echo Creating /dev
mount -o mode=0755 -t tmpfs none /dev
mknod /dev/console c 5 1
mknod /dev/null c 1 3
mknod /dev/zero c 1 5
mkdir /dev/pts
mkdir /dev/shm
echo Starting udev
/sbin/udevstart
echo -n "/sbin/hotplug" > /proc/sys/kernel/hotplug
echo "Loading dm-mod.ko module"
insmod /lib/dm-mod.ko
echo "Loading jbd.ko module"
insmod /lib/jbd.ko
echo "Loading ext3.ko module"
insmod /lib/ext3.ko
echo "Loading dm-mirror.ko module"
insmod /lib/dm-mirror.ko
echo "Loading dm-zero.ko module"
insmod /lib/dm-zero.ko
echo "Loading dm-snapshot.ko module"
insmod /lib/dm-snapshot.ko
/sbin/udevstart
echo Making device-mapper control node
mkdmnod
echo Scanning logical volumes
lvm vgscan
echo Activating logical volumes
lvm vgchange -ay
echo Making device nodes
lvm vgmknodes
echo Creating root device
mkrootdev /dev/root
umount /sys
echo Mounting root filesystem
mount -o defaults --ro -t ext3 /dev/root /sysroot
mount -t tmpfs --bind /dev /sysroot/dev
echo Switching to new root
switchroot /sysroot
umount /initrd/dev

regards,
Steven Chan

Re: fedora lvm root disk ....

K.C. Chan — Tue, 16 Aug 2005 14:52:51 GMT

So, is there an expert install option for fc3 or fc4 installations in which you can part your partition with lvm, carve out logical extend and create xfs file system for /boot and root file system?

Re: fedora lvm root disk ....

Steven Chan_9 — Tue, 16 Aug 2005 20:23:03 GMT

Hi KC,

Yes, you can setup LVM during the installation with Disk Druid in FC3 or FC4.

Actually, if you let Disk Druid part you hard drive automatically, the default setting is use LVM on your root. Of cause you can do this manually.

regards,
Steven Chan

Re: fedora lvm root disk ....

K.C. Chan — Wed, 17 Aug 2005 09:27:02 GMT

Will it create volume group and logical volume? What option do I use when booting off the cdrom to get full lvm support? Thanks.

Re: fedora lvm root disk ....

Steven Chan_9 — Wed, 17 Aug 2005 10:08:13 GMT

Hi KC,

When you install from the FCs' CD. During Disk Partition Setup, you will be asked for choosing Automatically Partition or Manually partition with Disk Druid.

Choose Automatically Partition and it will setup your hard drive with 1 partition for /boot and rest of part to a VG, then create a LV for / and another LV for swap.

regards,
Steven Chan