How do I reduce my EBS volume capacity without losing data? [closed]

Question

I would like to reduce EBS volume capacity without losing data.

I would like to change the capacity from 1 TB to 200 GB.

Please provide detailed steps on how to do it.

Answer 1

The approach I take to decreasing an EBS root volume is as follows:

Stop (not terminate) the target instance, and detach the root EBS volume. Alternatively, you can snapshot the root volume (or use an existing snapshot) and create a new EBS volume from that. (e.g. /dev/xvda1)

Note: the volume you use from the step above will be altered - so you may want to take a snapshot if you didn't already.

Create a new EBS volume that is the desired size (e.g. /dev/xvdg)

Launch an instance, and attach both EBS volumes to it

Check the file system (of the original root volume): (e.g.) e2fsck -f /dev/xvda1

Maximally shrink the original root volume: (e.g. ext2/3/4) resize2fs -M -p /dev/xvda1

Copy the data over with dd:
    Choose a chunk size (I like 16MB)

    Calculate the number of chunks (using the number of blocks from the resize2fs output): blocks*4/(chunk_size_in_mb*1024) - round up a bit for safety

    Copy the data: (e.g.) dd if=/dev/xvda1 ibs=16M of=/dev/xvdg obs=16M count=80

Resize the filesystem on the new (smaller) EBS volume: (e.g.) resize2fs -p /dev/xvdg

Check the file system (of the new volume): (e.g.) e2fsck -f /dev/xvdg

Detach your new EBS root volume, and attach it to your original instance