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I just converted by lvm2 root filesystem from linear lvm2 (single HDD:sda) to lvm2 raid1 (using lvconvert -m1 --type raid1 /dev/ubuntu/root /dev/sdb5 command). But after this conversion I can't boot my ubuntu 12.10 (kernel 3.5.0-17-generic).

Initramfs says that it can't find root fs in /dev/mapper:

Begin: Running /scripts/init-premount ... done.
Begin: Mounting root file system ... Begin: Running /scripts/local-top ... done.
... (kernel messages)
Gave up waiting for root device.  Common problems:
 - Boot args (cat /proc/cmdline)
   - Check rootdelay= (did the system wait long enough?)
   - Check root= (did the system wait for the right device?)
 - Missing modules (cat /proc/modules; ls /dev)
ALERT!  /dev/mapper/ubuntu-root does not exist.  Dropping to a shell!

There is my list of modules and cmdline: 

(initramfs) cat /proc/modules
hid_generic
usbhid
hid
e1000
raid10
raid456
async_pq
async_xor
xor
async_memcpy
async_raid6_recov
raid6_pq
async_tx
raid1
raid0
multipath
linear
(initramfs) cat /proc/cmdline
BOOT_IMAGE=/vmlinux-3.5.0-17-generic root=/dev/mapper/ubuntu-root ro
(initramfs) ls /dev/mapper
control     ubuntu-swap_1

There is output from lvm utility, which says that root LV is inactive / NOT available:

lvm> pvscan
  PV /dev/sda5    VG ubuntu   lvm2 [ 13.76 GiB / 408.00 MiB free]
  PV /dev/sdb5    VG ubuntu   lvm2 [ 13.76 GiB / 508.00 MiB free]
lvm> vgscan
  Reading all physical volumes. This may take a while...
  Found volume group "ubuntu" using metadata type lvm2
lvm> lvscan
  inactive        '/dev/ubuntu/root' [13.26 GiB] inherit
  ACTIVE          '/dev/ubuntu/swap_1' [100.00 MiB] inherit

lvm> lvdisplay ubuntu
  --- Logical volume ---
  LV Path                /dev/ubuntu/root
  LV Name                root
  VG Name                ubuntu
  LV UUID                xxxxxxxxxxxxxxx
  LV Write Access        read/write
  LV Creation host, time ubuntu, 2013-05-07
  LV Status              NOT available          <<<<< !!!!
  LV Size                13.26 GB
  Current LE             3394
  Mirrored volumes       2
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto

And lvchange -ay ubuntu fails from initrd in my case:

lvm>  lvchange -ay ubuntu
  /sbin/modprobe failed: 1
  Can't process LV root: raid1 target support missing from kernel?

Which module is missing in my initrd? Now I have full collection of modules from this kernel and can try any module.

osgx
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  • did you recreate initrd after the conversion? – ptman May 07 '13 at 15:30
  • ptman, no, I didn't. Only waited for full resync. Do you think, that `update-initramfs -u` will include dm-raid into initrd? – osgx May 07 '13 at 15:58
  • update-initramfs didn't include dm-raid into image; I needed to manually add this module to `/etc/initramfs-tools/modules` file. – osgx May 08 '13 at 08:28

1 Answers1

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You need this:

modprobe dm_raid

{pv,vg,lv}scan have a look at the disk and see the LVs there. But as the kernel cannot provide access to them in the configured way they are not available for access.

Hauke Laging
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  • insmod dm_raid helped but I still needed to do `lvchange -ay ubuntu` to boot. – osgx May 07 '13 at 16:25
  • @osgx Sure. The kernel module **enables** you to make the `lvchange` call. That was your problem, wasn't it? It doesn't **replace** the call. If it did, all VGs would always be (or at least start) active. – Hauke Laging May 07 '13 at 16:29
  • Hauke, my first problem was that I can't boot after lvconvert. Part of it - is that i have no dm-raid module in initramfs. – osgx May 07 '13 at 16:31
  • @osgx I meant "the problem you asked for" as you had already tracked the solution of your bigger problem down to a missing kernel module. – Hauke Laging May 07 '13 at 16:33