SLES10 with EVMS missing root past boot

2007-04-23 by Thomas Lotterer

When I installed my SLES10 I had to install it on EVMS to enable testing of NSS. This weekend it was time to reboot the machine after a kernel update. However, a dreadful message appeared on my screen “Waiting for device /dev/evms/lvm2/system/root to appear: … not found” – All filesystems gone!

Fortunately, after some fiddling with the boot process I luckily found out that the data was still there. The kernel update just ran mkinitrd(8) with default options, leaving the initial ramdisk without EVMS support. Here is how I recovered my system:

- boot with the SLES10 AMD64/EMT64 CD1, because for some reason my SOHO server does not boot the DVD. Also it boots other DVDs and the SLES DVD boots in other machines.

- while inside the grub menu, replace the CD1 with the DVD

- boot to rescue mode and enter bash

- sidenote: to access a CD/DVD at this point, use
#  modprobe ide-cd; mkdir -p /mnt; mount /dev/hda /mnt

- probe EVMS information
# echo "probe" | evms -s

- query devices
# echo "q:d" | evms -s

- query volumes, this should display the name your root container
# echo "q:v" | evms -s

- mount root (note the comma in the mount command)
# mkdir -p /old
# echo "mount:/dev/evms/lvm2/system/root,/old" | evms -s

- you should see your valuable data on the old root
# ls -l /old/

- turn your old root into the current root
# chroot /old

- create a new EVMS ramdisk
# /sbin/mkinitrd -f evms

- shutdown properly and reboot
# init 6
or press CTRL+ALT+DEL

- further reading in Novell SLES 10 Documentation

4 Responses to “SLES10 with EVMS missing root past boot”

  1. Daniel Says:

    Thanks for your advice.

    However, I’m a bit puzzled.
    If i boot with a CD to rescue mode and enter bash,
    how can i run the command “mkdir -p /old”?
    In my case, SuSE prompts something like “write protected”

    Thanks in advance.

  2. Thomas Lotterer Says:

    Booting from CD into rescue mode runs a small but complete system inside memory, including the root filesystem. The “mkdir -p /old” creates a highly volatile mountpoint. Nevertheless, you can mount real storage to it.

  3. Alex Says:

    Tom, I agree with Daniel. My SLES 10 throughs the same ‘write protected’ error when I try to mkdir.

  4. JP Says:

    you can use the /media or /mnt folders already existing on the system:
    mount /dev/evms/lvm2/system/sys_linux (or whatever your evms volume is) /mnt
    — should work

Leave a Reply