[linux-lvm] Unable to boot using LVM for "/"

[linux-lvm] Unable to boot using LVM for "/"

[Les Hazelton]

I have been attempting to move my root partition to a logical volume and
eliminate the current normal partition.  No luck.  I have read the
lvmcreate_initrd man page found at 

http://linux.msede.com/lvm/man/man2html.cgi?lvmcreate_initrd:8

and followed those instructions but it doesn't work for me. I have tried
two different versions of lilo (lilo-0.21.5.1-4mdk and the 0.21.6
binaries from the lilo site) and get the same result from both.

If I use grub with the menu.lst shown below I can boot the entry for
linux-2 and the system runs correctly. Neither of the other two entries
will boot correctly. The /dev/hda9 is the real partition I am attempting
to eliminate.  If I try to boot the first, linux, entry it gets a kernel
panic because it can't locate init. The third entry produces a kernel
panic because it can't mound device 0:0
---------------------------------------------------------
[root@farpt1 /root]# cat /boot/grub/menu.lst
timeout 5
color black/cyan yellow/cyan
i18n (hd0,4)/grub/messages
keytable (hd0,4)/us.klt
default 0

title linux
kernel (hd0,4)/bzImage-2.2.17-0.16mdk-02 init=/boot/init  vga=0x318
initrd (hd0,4)/initrd.lrh.gz

title linux-2
kernel (hd0,4)/bzImage-2.2.17-0.16mdk-02  root=/dev/hda9 vga=0x318
initrd (hd0,4)/initrd.gz

title test
kernel (hd0,4)/bzImage-2.2.17-0.16mdk-02 root=/dev/vg01/main vga=0x318
initrd (hd0,4)/initrd.lrh.gz
----------------------------------------------------------

When the system is booted from the linux-2 entry it produces the
following.  Notice the rdev and "df -h" show clearly different views of
where the root partition is sourced.
----------------------------------------------------------
[root@farpt1 /root]# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/vg01/main        501M  353M  122M  74% /
/dev/hda5             235M  2.9M  220M   1% /boot
/dev/vg01/usr         2.5G  2.0G  553M  78% /usr
/dev/vg01/src         600M  380M  220M  63% /usr/src
/dev/vg01/local       800M  600M  200M  75% /usr/local
/dev/vg01/home       1020M  434M  586M  43% /home
/dev/vg01/mp3         1.5G  1.4G   98M  94% /mp3
/dev/vg01/var         252M  122M  129M  49% /var
/dev/hda8             2.9G  1.3G  1.5G  47% /Archives
[root@farpt1 /root]# rdev
/dev/hda9 /
------------------------------------------------------------

My lilo.conf resides in the /boot partition which is an ext2fs on
/dev/hda5. It is listed below.  When I install lilo and try to boot the
system It comes up but it is using /dev/hda6 for the root partition and
that belongs to my test copy of LM v7.2 and should have nothing to do
with this system. 

The one thing that is clearly different is that the lvmcreate_initrd man
page references ext2fe file systems and I am using reiserfs for all
except the /boot on /dev/hda5. Can anyone see what I am doing wrong and
get me turned around?  I would sure appreciate the help.

---------------------------------------------
[root@farpt1 /root]# cat /boot/lilo.conf
boot=/dev/hda5
map=/boot/map
install=/boot/boot.b
vga=ext
default=rootonly
keytable=/boot/us.klt
lba32
delay=100
backup=/boot/boot.grub
message=/boot/message
image=/boot/bzImage-2.2.17-0.16mdk-02 vga=0x318
    initrd=/boot/initrd.gz
	root=/dev/vg01/main
	label=rootonly
	append="ramdisk_size=8192"
	read-only
--------------------------------------------------------------

-- 

Good Journey, longevity and prosperity to all

Les Hazelton

Re: [linux-lvm] Unable to boot using LVM for "/"

[Charles Duffy]

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On Mon, Oct 09, 2000 at 03:28:22PM -0400, Les Hazelton wrote:
> I have been attempting to move my root partition to a logical volume and
> eliminate the current normal partition.  No luck.  I have read the
> lvmcreate_initrd man page found at 
> 
> http://linux.msede.com/lvm/man/man2html.cgi?lvmcreate_initrd:8
> 
> and followed those instructions but it doesn't work for me. I have tried
> two different versions of lilo (lilo-0.21.5.1-4mdk and the 0.21.6
> binaries from the lilo site) and get the same result from both.
> 
> If I use grub with the menu.lst shown below I can boot the entry for
> linux-2 and the system runs correctly. Neither of the other two entries
> will boot correctly. The /dev/hda9 is the real partition I am attempting
> to eliminate.  If I try to boot the first, linux, entry it gets a kernel
> panic because it can't locate init. The third entry produces a kernel
> panic because it can't mound device 0:0

"root=/dev/vg01/main" fails because the kernel, when booting, just
determines the major/minor numbers for the root partition based on
looking up the root device in a fixed table. What you need to do to
get the "test" entry running is change the root to the major/minor
number combo in hex; in my case, where /dev/vg01/root has major/minor
number 58,3 in decimal, I pass "root=3a03" to grub and that works
correctly.

Note that the above presumes that the initrd runs correctly. Does it?
(Be aware that I had to add /dev/console and /dev/tty0 entries to the
initrd to see output from the programs run from it... this may have
been fixed by now, or maybe not).

Hope this has been of some use.

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Re: [linux-lvm] Unable to boot using LVM for "/"

[Les Hazelton]

Charles Duffy wrote:
---------snip ----------------
> 
> "root=/dev/vg01/main" fails because the kernel, when booting, just
> determines the major/minor numbers for the root partition based on
> looking up the root device in a fixed table. What you need to do to
> get the "test" entry running is change the root to the major/minor
> number combo in hex; in my case, where /dev/vg01/root has major/minor
> number 58,3 in decimal, I pass "root=3a03" to grub and that works
> correctly.
> 
> Note that the above presumes that the initrd runs correctly. Does it?
> (Be aware that I had to add /dev/console and /dev/tty0 entries to the
> initrd to see output from the programs run from it... this may have
> been fixed by now, or maybe not).
> 
> Hope this has been of some use.

Actually, it was a great help.  I have it working now - sort of.  The
problem was in two parts. I changed the grub menu.lst to pass
"root=3a06" as you suggested and that changed some of the symptoms. When
it still didn't work as expected I reread the lvmcreate_initrd script.
It finally sunk in. The initrd creates the ram disk file system as ext2
and I had created my root LV using reiserfs.

This creates a conflict between the initrd root file system and the one
on the logical volume and the mount won't work.  I re-formatted my LV
with mke2fs and made some changes to /etc/fstab. Now it works as
expected. It looks to me like you can't use reiserfs for the root file
system unless the initrd ram disk can be created using reiserfs. I don't
think that will work.

-- 

Good Journey, longevity and prosperity to all

Les Hazelton

Re: [linux-lvm] Unable to boot using LVM for "/"

[Les Hazelton]

Charles Duffy wrote:
> 
> On Mon, Oct 09, 2000 at 11:35:37PM -0400, Les Hazelton wrote:
> > Actually, it was a great help.  I have it working now - sort of.  The
> > problem was in two parts. I changed the grub menu.lst to pass
> > "root=3a06" as you suggested and that changed some of the symptoms. When
> > it still didn't work as expected I reread the lvmcreate_initrd script.
> > It finally sunk in. The initrd creates the ram disk file system as ext2
> > and I had created my root LV using reiserfs.
> >
> > This creates a conflict between the initrd root file system and the one
> > on the logical volume and the mount won't work.  I re-formatted my LV
> > with mke2fs and made some changes to /etc/fstab. Now it works as
> > expected. It looks to me like you can't use reiserfs for the root file
> > system unless the initrd ram disk can be created using reiserfs. I don't
> > think that will work.
> 
> That's interesting, as I'm using reiserfs for my root filesystem
> without issues (though getting it up was a bit of a challenge, and I
> modified lvmcreate_initrd quite heavily). I'm also quite certain that
> one can switch from a minix-based initrd to an ext2-based root.
> 
> If you wouldn't mind recounting your symptoms, I'd be curious to hear
> what happened.

At this point I am a bit confused.  I saw your note indicating you used
reiserfs for the root file system so I figured I better double check
what I had done. 

Having made the change you previously suggested, I now had one working
setup with the root on a logical volume. That filesystem was ext2. I
made another LV with a reiserfs filesystem, copied all the root
components into it and updated its etc/fstab entries. I set the
/boot/grub/menu.lst to reflect these new conditions and re-booted the
system.

Now the root filesystem on a reiserfs LV is working just fine. In fact,
I can reboot between the two different root configurations using the
exact same initrd.gz file and everything appears to be correct. The
initrd.gz file was made with an unmodified lvmcreate_initrd script. 

I can only assume I was working too late when I did the other tests. 
Sorry for any confusion I may have caused.

-- 

Good Journey, longevity and prosperity to all

Les Hazelton