How to mount another EBS as /var on EC2 (ubuntu)

mount_ebs.sh

#!/bin/bash
#attach the EBS to /dev/sdf before running it

# If not mounted... format EBS
mkfs -t ext4 /dev/xvdb
mkdir /mnt/new
mount /dev/xvdb /mnt

#copy original /var to /dev/xvdb
sudo cp -ax /var/* /mnt
cd /
sudo mv var var.old # just in case

#mount EBS as new /var
umount /dev/xvdb
sudo mkdir /var
sudo mount /dev/xvdb /var
sudo rm -rf /var.old/

#update fstab file to mount EBS on system startup
echo "/dev/xvdb /var ext4 noatime 0 0" >> /etc/fstab