How to do a hard disk upgrade using LVM?

[adrian_stephens]

Ideally I'd like to see a HOWTO that shows how to do a hard disk upgrade
for a system using LVM.

Here's how I did it (probably breaking all the rules, but hey it works!).
1. Fdisk created identical size partitions for new /boot and lvm physical volume
to the old partitions.
2. Used DD in single user mode to copy across the old contents
3. Swapped to new hard drive
4. Added partition for remainder of hard disk using fdisk
5. added that partition to the volume group and then extended / to use the info.

This all worked, but it took some time to discover the gotchas. Also, this is
not scalable, because each time I do this, I'm going to increase the number of
partitions comprising the volume group.

Observations along the way:
1. Parted had trouble with my old disk (auto formatted during FC3 install). It got
the geometry wrong, and wouldn't operate on it. I suspect it would be easier to copy
the partitions with it.

2. I thought that Parted "resize" partition was what I wanted - but this doesn't work with
lvm partions. Sigh.

3. Fdisk can be made to create partitions of exactly the right size, regardless of geometry by specifying the size in sectors.

4. pvresize sounds like it might do what I want. But this isn't there yet.

Someone, please tell me a cleaner way to do it!

[df12]

I know this isn't really what you are looking for but I recently added an 80gig HDD (hde) to my LVM data volume (/dev/vg00/lvol00).

1. pvcreate /dev/hde
2. vgextend vg00 /dev/hde
3. lvextend -L 80G /dev/vg00/lvol00 /dev/hde
4. e2fsck -f /dev/vg00/lvol00
5. resize2fs -p /dev/vg00/lvol00

Some things to consider, I'd suggest getting the latest version of e2fsprogs before begining this process. The version in FC3 has some *issues* you might run into otherwise. The fsck in step 4 above is required before resizefs will function...

[adrian_stephens]

Thanks for the info, I'd missed that I needed to resize the filesystem too. It's obvious when you say it.

Anyway, I booted into rescue mode, using lvm I did: vgscan and vgchang -ay.
Then I did the e2fsck and resize2fs as you describe.
Then I rebooted.

During reboot, the system complained that there was some problem with the filesystem and dropped into maintenance mode. It suggested I run fsck.

So, I ran fsck. There were several hundred errors of the form:
"Group inode bitmap at xxxx conflicts with some other fs block"

System restarted and ran, and I don't see any problems despite the rather scary errors above.


I'm pretty sure the way I approached this was wrong. I shouldn't try and copy the partition, but I should create a separate volume group using the larger device, create logical volumes on it, format and mount these. Copy across the files.

It's my guess that, given that the kernel already supports lvm, the only changes necessary in the /boot partion would be to update the name of the volume group/logical volume in the grub menu.

[df12]

Yep, that's the e2fsprogs gotcha I mentioned. you need to get version 1.36 of e2fsprogs. Oddly enough they just made those updated rpms available through up2date or yum. Basically once you have the new e2fsprogs you'll have to do the following:

1. debugfs -w /dev/vg00/lvol00 -R "features ^resize_inode"
2. e2fsck -f /dev/vg00/lvol00

you'll need e2fsprogs 1.36 for this to work, 1.35 is/was the default in FC3.

---Edit---
I might have misread your post, if running fsck as you did, did not fix the errors then you'll probably have to do the steps above.