Re: [linux-lvm] lvm2 conf on boot disk

[Alfredo De Luca <alfredo.deluca@gmail.com>]

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Hi Jack.
Thanks for that. I did pretty much what you said but not sure how to
re-create the initrd then install the grub.
Do you have a specific procedure?
I followed the procedure in attachment but it's slightly different
from what I am looking for.


On Thu, Jul 10, 2014 at 2:46 AM, Jack Waterworth <jack@redhat.com> wrote:
> There is no way to do an in-place convert from a partitioned device to LVM
> without losing data. I would recommend adding a new disk, reinstall the OS
> on the new disk with LVM, and then moving over any data that was required
> after installation.
>
> You may be able to do this in rescue mode within a chrooted environment, but
> things could get messy. Add the new device, build the lvm stack, copy over
> the data then chroot into the NEW lvm root. Mount everything appropriately,
> recreate the initrd and re-install grub onto the new disk.  Go in with the
> expectation that you may be fixing things after the reboot from rescue mode.
>
>   Jack Waterworth, RHCE
>   Senior Technical Support Engineer
>   Red Hat Global Support Services
>   919.610.2024 -- jack@redhat.com
>
> On 07/08/2014 05:56 AM, Alfredo De Luca wrote:
>>
>> Hi all.
>> I have red hat 5.7 with no lvm2 installed. Now I want to configure
>> lvm2 on the root and swap partition then later on adding a couple of
>> LUNs to create a VG
>> What's the best practice/procedure to install lvm2 on the boot disk?
>> Is it possible? I guess I have to run Linux CD in rescue mode
>>
>> Regards
>>
>>
>
> _______________________________________________
> linux-lvm mailing list
> linux-lvm@redhat.com
> https://www.redhat.com/mailman/listinfo/linux-lvm
> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/



-- 
Alfredo

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A.) First Create an LVM partition:

# pvcreate /dev/sdb1  ---->>> or the any other device as per your server.
# vgcreate vg_new_root  /dev/sdb1
# lvcreate -L 4G -n lv0 vg_new_root
 

B.) Format this new LVM partition with ext3 or ext4 (or as needed):

# mke2fs -j /dev/vg_new_root/lv0
 

C.) Create a new mount point and then mount the LVM Partiton on it:

# mkdir /mnt/NEW_ROOT_PARTITION
# mount /dev/vg_new_root/lv0  /mnt/NEW_ROOT_PARTITION


D.) Copy all contents of "/" to the newly mounted folder:

# tar -cvpf - --one-file-system --acls --xattrs --selinux / | tar -C /mnt/NEW_ROOT_PARTITION -xf
# cp -aux /dev /mnt/NEW_ROOT_PARTITION


E.) Now edit the file -- "/mnt/NEW_ROOT_PARTITION/etc/fstab" to reflect the new root:

/dev/vg_new_root/lv0            /                       ext3    defaults        1 1

 

F.) Now it is needed to chroot to new filesystem and create initrd with raid and lvm support:

# mount --bind /dev  /mnt/NEW_ROOT_PARTITION
# chroot /mnt/NEW_ROOT_PARTITION
# mount -t proc /proc /proc
# mount -t sysfs /sys /sys

# vgscan
# vgchange -ay
# mkinitrd -v /boot/initrd-`uname -r`.lvm.img `uname -r`
   
# umount /sys
# umount /proc
# exit
# mv /mnt/lv0/boot/initrd-`uname -r`.lvm.img /boot


G.) Edit "/boot/grub/grub.conf" to point to new root "/dev/vg_new_root/lv0". Backup the old initrd in "/boot" directory and rename the new initrd to the existing one or edit the entry in grub.conf.

 

H.) Reboot