[RndTbl] "un-RAIDing" a Linux P2V

[Wyatt Zacharias]

Loading dm-mem-cache.ko module
Loading dm-region_hash.ko module
Loading dm-message.ko module
Loading dm-raid45.ko module
device-mapper: dm-raid45: initialized v0.25941
Waiting for driver initialization.
Scanning and configuring dmraid supported devices
Trying to resume from /dev/vg00/lvol00
Unable to access resume device (/dev/vg00/lovl00)
Creating root device.
Mounting root filesystem.
mount: could not find filesystem '/dev/root'
Settting up other filesystems.
Setting up a new root fs
setuproot: moving /dev/ failed: No such file or directory
no fstab.sys, mounting internal defaults
setuproot: error mounting /proc: No such file or directory
setuproot: error mounting /sys: No such file or directory
Switching to new root and running init.
unmounting old /dev
unmounting old /proc
unmounting old /sys
switchroot: mount failed: No such file or directory
Kernel panic - not sycing: Attempted to kill init!

So here's the last section of the boot log before it panics, I've also
tried with 'noresume' in the kernel options, and that gets rid of the
resume device error. So it looks like something's wrong at mkrootdev step.
Is there a way to debug what devicemapper is doing to tell if it's picking
up the logical volumes correctly?

echo "Loading dm-raid45.ko module"
stabilized --hash --interval 1000 /proc/scsi/scsi
mkblkdevs
echo Scanning and configuring dmraid supported devices
resume /dev/vg00/lvol00
echo Creating root device.
mkrootdev -t ext4 -o defaults,ro /dev/vg00/lvol01
echo Mounting root filesystem.
mount /sysroot
echo Setting up other filesystems.
setuproot
echo Switching to new root and running init.
switchroot



--
Wyatt Zacharias


On Mon, Nov 30, 2015 at 2:19 PM, Adam Thompson <athompso at athompso.net>
wrote:

> What's the partition type set to?  0xFD or 0x8E, by any chance?  Should
> probably be 0x83 for /boot, 0x8e for the PV.
> Otherwise, start from scratch instead of trying to "fix" it and you'll
> find the problem faster.
> VM boots? Yes.
> Loads boot sector? Yes.
> Loads GRUB? Yes.
> Loads kernel? Yes.
> Loads initrd? Maybe... probably.
> Can pivot_root? Maybe... probably not.
> Can achieve multi-user runlevel? No.
>
> So somewhere between loading initrd (which probably worked) and pivot'ing
> root (probably) lies your problem.  Extract your initrd and trace through
> the behaviour one line at a time.
>
> Better yet, examine what modules are baked into the original initrd (from
> the original physical server) and compare with the P2V'd list of modules.
>
> The loading of dm_raid is harmless; your problem is LVM modules or
> detection somehow.
>
> -Adam
>
>
> On 15-11-30 01:25 PM, Wyatt Zacharias wrote:
>
> So I'm attempting to virtualize one of our Redhat 5 boxes using VMWare's
> P2V functionality, and it's copied all the data into the VM without any
> trouble, but now I can't seem to get the virtual machine to boot because
> it's not detecting the virtualized partitions correctly. The physical
> system was using LVM on top of dm-raid to local disks. When VMWare
> virtualized the disks, it created a single disk, and copied the LVM layout
> onto it, so I think what's happening is on boot, the system is looking for
> the RAID disks and can't find them. When I try to boot it, it says that it
> can't find the logical volumes and goes into a kernel panic.
>
> I've booted with a rescue disk, and when I run a pvscan on the new virtual
> disk, all the volumes are there and can be mounted, so the problem must be
> that the system isn't looking for the volumes in the right place. I've
> tried changing the root device to /dev/sda in the device.map comfig file,
> and I rebuilt the initrd file with both the --force-lvm-probe and
> --omit-raid-modules and it still loads dm-raid on boot.
>
> So how do I get the system to completely forget about RAID, and boot off
> the new virtual disk? Is there a RAID config somewhere that I'm missing?
>
> --
> Wyatt Zacharias
>
>
>
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