From my point of view the only benefit for instance store is that it has

better IO..though if you build a RAID using several EBS volumes.

Anyway steps are : 

1. create 1 EBS volume
2. attach this volume to your EC2 instance store 

3. format it as ext3
mkfs.ext3 /dev/sdf

4. mount it
mkdir /mnt/ebs
mount /dev/sdf /mnt/ebs

5. sync the instance with the volume
rsync -avHx / /mnt/ebs
rsync -avHx /dev /mnt/ebs

(you can edit /mnt/ebs/fstab and delete the reference towards the /mnt partition)

6. sync && umount /mnt/ebs

7. create a snapshot of that volume

8. register the ami based on that snapshot

ec2-register -s snap-ID -name "EBS instance" -description "EBS instance" -architecture i386

 -ramdisk ari-d23cd6bb -kernel aki-c43cd6ad

As a result it should show something like:

IMAGE   ami-newID

WARNING: mismatch_cnt is not 0 on /dev/md1

The /dev/mdX can vary depending on how many raid partitions you have. This mismatch_cnt value is the value of the blocks,

that are not synchronized between RAID-1 (mirrored) drives.  On my server it looked something like :

[root@ns ~]# cat /sys/block/md1/md/mismatch_cnt
4910080

To fix :

echo repair >/sys/block/md0/md/sync_action
watch cat /proc/mdstat

And after the repair is completed:

echo check >/sys/block/md1/md/sync_action
watch cat /proc/mdstat

Then check to see what this returns:

cat /sys/block/md1/md/mismatch_cnt

node0001:/etc/lvm# lvdisplay
— Logical volume —
LV Name /dev/lvm1/usr
VG Name lvm1
LV UUID Be0rAE-Y3q8-1aHM-WUDN-pDXU-57B2-sNHYmg
LV Write Access read/write
LV Status available
# open 1
LV Size 4.66 GB
Current LE 1192
Segments 1
Allocation inherit
Read ahead sectors auto
– currently set to 256
Block device 253:0

— Logical volume —
LV Name /dev/lvm1/var
VG Name lvm1
LV UUID ttng8k-54zQ-Rr5M-OjlW-gopL-fPzQ-0Frd3o
LV Write Access read/write
LV Status available
# open 1
LV Size 14.90 GB
Current LE 3814
Segments 1
Allocation inherit
Read ahead sectors auto
– currently set to 256
Block device 253:1

— Logical volume —
LV Name /dev/lvm1/tmp
VG Name lvm1
LV UUID ZuhigP-u3iE-JGQn-biWR-c5It-QivP-LJqXz9
LV Write Access read/write
LV Status available
# open 1
LV Size 952.00 MB
Current LE 238
Segments 1
Allocation inherit
Read ahead sectors auto
– currently set to 256
Block device 253:2

— Logical volume —
LV Name /dev/lvm1/root
VG Name lvm1
LV UUID pF0GYz-KyhM-H9Gm-rDEs-zmo1-hyj7-I8XO74
LV Write Access read/write
LV Status available
# open 1
LV Size 46.56 GB
Current LE 11920
Segments 1
Allocation inherit
Read ahead sectors auto
– currently set to 256
Block device 253:3

— Logical volume —
LV Name /dev/lvm1/swap
VG Name lvm1
LV UUID LyLQSt-HiVw-Yh84-WB0Y-uhLI-Z0p3-3sZiBf
LV Write Access read/write
LV Status available
# open 1
LV Size 7.45 GB
Current LE 1907
Segments 1
Allocation inherit
Read ahead sectors auto
– currently set to 256
Block device 253:4

Show attributes of physical volume:

node0001:~# pvdisplay
— Physical volume —
PV Name /dev/md2
VG Name lvm1
PV Size 923.36 GB / not usable 896.00 KB
Allocatable yes
PE Size (KByte) 4096
Total PE 236380
Free PE 196579
Allocated PE 39801
PV UUID W5Iaek-T5zk-rAjd-J2qI-CNt1-nan2-1k6xsK