LVM and hard disk upgrade
Hello,
I have a fresh (few days old) installation of Lenny (Debian 5.0,
stable) system. This installation was performed on single disk - used
drive, unfortunately. As S.M.A.R.T is reporting potential disk
failure, I need to move the system to a new HDD. This new drive is
bigger than the current one, so I can't just 'dd' from old one to the
new (and I'm not even sure if this could work - because of UUIDs
different for new disk?).
In LVM-HOWTO I found procedure for removing old drives from volume
group. Just create new PV on new disk, add the new PV to volume group,
move existing data out of old physical volume using 'pvmove old_pv
new_pv', remove old disk from volume group using 'vgreduce' and remove
old drive, rebooting the system.
I guess this could work if only /home (or similar, not important
during bootup filesystems) were on LVM, but default Debian install
leaves only /boot on normal partition, putting all the rest (/, /home,
swap) on LVM logical volumes.
But when / is on LVM, I expect trouble booting system from new disk
(changed UUIDs? wrong root LV label in initramfs?)
What steps do I need to perform to be able to boot system from new
disk? Had anyone do similar operation?
New disk will be temporairly /dev/hdc, and after upgrade it will be
moved to /dev/hda, in place of current faulty one. Does it influence
PV name (currently /dev/hda2, on new disk it will probably be
/dev/hdc2)?
Simple 'update-grub', after booting from any LiveCD (like GRML) and
chrooting to new disk, would do? Or maybe I have to update initramfs to
point to correct PV (or does it use only LV and initramfs's devmapper
should figure it out, that root is on different PV now)
My system's current layout is:
/etc/fstab (stripped from unimportant data)
/dev/mapper/mongoose--vg01-root / ext3
/dev/hda1 /boot ext2
/dev/mapper/mongoose--vg01-home /home ext3
/dev/mapper/mongoose--vg01-swap_1 none swap
# fdisk -l /dev/hda
Device Boot Start End Blocks Id System
/dev/hda1 * 1 31 248976 83 Linux
/dev/hda2 32 24321 195109425 8e Linux LVM
# vgdisplay
--- Volume group ---
VG Name mongoose-vg01
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 4
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 3
Open LV 3
Max PV 0
Cur PV 1
Act PV 1
VG Size 186,07 GB
PE Size 4,00 MB
Total PE 47634
Alloc PE / Size 47634 / 186,07 GB
Free PE / Size 0 / 0
VG UUID NygOpX-FYnl-xCqn-Lp2w-xJ5X-Yshs-cRvNND
# pvdisplay
--- Physical volume ---
PV Name /dev/hda2
VG Name mongoose-vg01
PV Size 186,07 GB / not usable 561,00 KB
Allocatable yes (but full)
PE Size (KByte) 4096
Total PE 47634
Free PE 0
Allocated PE 47634
PV UUID QSWVsg-wAMw-SMA4-ES0N-0bFi-otbn-A3EzXS
# lvdisplay
--- Logical volume ---
LV Name /dev/mongoose-vg01/root
VG Name mongoose-vg01
LV UUID AK2MWV-EqId-duJm-5i10-Kche-ktwt-suw12y
LV Write Access read/write
LV Status available
# open 1
LV Size 6,52 GB
Current LE 1668
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 254:0
--- Logical volume ---
LV Name /dev/mongoose-vg01/swap_1
VG Name mongoose-vg01
LV UUID 18unpG-yVB6-lGdP-jIiH-Pcqd-iYv9-VL5uRA
LV Write Access read/write
LV Status available
# open 2
LV Size 732,00 MB
Current LE 183
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 254:1
--- Logical volume ---
LV Name /dev/mongoose-vg01/home
VG Name mongoose-vg01
LV UUID 6NBBNw-Nd3e-K2bp-Ds7p-R9UY-qs1S-JSml9y
LV Write Access read/write
LV Status available
# open 1
LV Size 178,84 GB
Current LE 45783
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 254:2
and relevant entries from /boot/grub/menu.lst
title Debian GNU/Linux, kernel 2.6.26-1-686
root (hd0,0)
kernel /vmlinuz-2.6.26-1-686
root=/dev/mapper/mongoose--vg01-root ro
initrd /initrd.img-2.6.26-1-686
title Debian GNU/Linux, kernel 2.6.26-1-686 (single-user
mode)
root (hd0,0)
kernel /vmlinuz-2.6.26-1-686
root=/dev/mapper/mongoose--vg01-root ro single
initrd /initrd.img-2.6.26-1-686
--
Cheers,
Jacek Politowski
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