How to increase EBS volume size - EBSのディスクサイズを増やす方法

This article is written about that in detail.
この記事がわかりやすいです。

http://www.e-zest.net/blog/simple-steps-to-change-size-of-ebs-volume-in-ec2-of-aws-using-aws-console/

1. Create snapshot of existing (old) volume
2. Then create new volume from created snapshot with new size
3. Put new size there
4. Stop running instance
5. Detach current volume
6. Attach newly created volume in step 2 with Device as /dev/sda1 (It works only with /dev/sda1)
7. Then check with elastic IP address
8. Then start instance.If you are not able to log-in, there release IP and attach again and then start instance
9. Finally after you gets connected through putty using either ec2-user for fedora/Amazon AMI and root for centOS
10. Run following commands

sudo su
sudo resize2fs /dev/sda1