Migrating a linux machine from LVM to normal partitions

Before shutting down your system, copy the output of your current fstab in order to mount your partitions:

# cat /etc/fstab

Boot from a live cd (I used an ubuntu 14.04)
You 've got to mount somewhere the original filesystem in order to copy it, preferably as read-only:
Assuming our old disk is /dev/sda with 3 partitions (all of them LVM):

# mkdir /mnt/olddisk /mnt/olddisk/oldboot /mnt/olddisk/oldroot /mnt/olddisk/oldvar 
# mount -o ro /dev/mapper/vg1-lv_XXX /mnt/olddisk/oldboot
# mount -o ro /dev/mapper/vg1-lv_XXY /mnt/olddisk/oldroot
# mount -o ro /dev/mapper/vg1-lv_XXZ  /mnt/olddisk/oldvar

Your old fstab should look like this

# cat /mnt/olddisk/oldroot/etc/fstab

/dev/mapper/vg1-lv_XXX   /                       ext3    defaults        1 1
/dev/mapper/vg1-lv_XXY  /boot                   ext3    defaults        1 2
/dev/mapper/vg1-lv_XXZ  /var                  ext3    defaults        1 2
tmpfs                   /dev/shm                tmpfs   defaults        0 0
devpts                  /dev/pts                devpts  gid=5,mode=620  0 0
sysfs                   /sys                    sysfs   defaults        0 0
proc                    /proc                   proc    defaults        0 0
/dev/mapper/vg1-lv_swap      swap                    swap    defaults        0 

You should first check the inode size of your old disk because after migrating a disk with inode size 128 to a disk with inode size 256 which is the default now, grub won't install, you will get an error (The file /boot/grub/stage1 not read correctly, Error 2: Bad File or Directory Type)!

# tune2fs -l /dev/sda1 | grep -i 'inode size'

Inode size:           128

Fdisk your new disk (/dev/sdb)
I used 2 partitions, sdb1 for the the whole filesystem and of course a small swap sdb2 partition

# fdisk /dev/sdb

After creating both partitions, give sda1 the bootable flag (a) and change the system id to sdb2 (t, 82).

Format the partitions:

# mkfs.ext3 /dev/sdb1 -I 128
# mkswap /dev/sdb2

Label the partition makes it more convenient for configuring grub and fstab later:

I labeled it "root"

# e2label /dev/sdb1 root

Mount and prepare the filesystem on new disk:

# mkdir /mnt/newdisk
# mount /dev/sdb1 /mnt/newdisk
# cd /mnt/newdisk; mkdir {dev,mnt,boot,opt,usr,var,tmp,home,data}

Create and configure permissions on /proc, /dev and /sys folders:

# mkdir /mnt/newdisk/{proc,dev,sys}
# chmod -w /mnt/newdisk/proc
# chmod go+w /mnt/newdisk/dev
# chmod +t /mnt/newdisk/dev

copy all data from all olddisk mountpoints excluding /dev, /proc and /sys

# rsync -avz /mnt/olddisk/oldboot /mnt/newdisk --exclude dev --exclude proc --exclude selinux --exclude sys
# rsync -avz /mnt/olddisk/oldroot /mnt/newdisk --exclude dev --exclude proc --exclude selinux --exclude sys
....

Adjust some important permissions:

# chmod +t /mnt/newdisk/tmp
# chmod go+rw /mnt/newdisk/tmp

Installing grub on new disk requires chrooting:

# mount -o bind /dev /mnt/newdisk/dev
# chroot /mnt/newdisk
# grub
> root (hd1,0)
> setup (hd1)
> quit

Note that hd1 is /dev/sdb1 in our case

Fix grub:

# nano /boot/grub/grub.conf

change the line containing the image(s):

 /boot/vmlinuz-3.2.0-4-686-pae ro root=/dev/mapper/vg1-lv_XXX

  to

  /boot/vmlinuz-3.2.0-4-686-pae ro root=LABEL=root

or by UUID:

/boot/vmlinuz-3.2.0-4-686-pae ro root=UUID=a53bee3f-3a18-45b3-9b7a-8e8e0f2b3e1b 

you can get your UUID by:

# blkid /dev/sda1

Configure fstab:

# nano /etc/fstab

/dev/sda1    /                       ext3    defaults        1 1
tmpfs                   /dev/shm                tmpfs   defaults        0 0
devpts                  /dev/pts                devpts  gid=5,mode=620  0 0
sysfs                   /sys                    sysfs   defaults        0 0
proc                    /proc                   proc    defaults        0 0
/dev/sda2       swap                    swap    defaults        0 0

I removed all LVM mounts, and configured one mount for my root filesystem, and a second one for swap
You could use disk UUID instead of /dev/sdax:

UUID=a53bee3f-3a18-45b3-9b7a-8e8e0f2b3e1b /                       ext3    defaults        1 1
UUID=83a41156-85aa-4c40-a6db-b20d42fcb444       swap                    swap    defaults        0 0

Exit chroot after saving your fstab:

# exit