How to increase Disk Size in EC2

Method -1

Attached volume as a secondary harddisk

then we need to mount that drive in that instance

Method -2

Log into the AWS Management Console
Make sure that the Instance that you wish to change is not currently running
Navigate to Elastic Block Store > Volumes
Check the box next to the Volume that needs more space
Click the More… drop down list and select Create Snapshot
Enter a Name and a Description
Navigate to Elastic Block Store> Snapshots
Monitor the progress of the Snapshot for completion
Once complete, navigate back to Elastic Block Store > Volumes
Click Create Volume
Enter the desired size for the new volume
Make sure that you select the same Availability Zone for your instance
Select the Snapshot that you just created
Click Yes, Create
Monitor the progress of the Volume for completion
Once complete, Check the box next to the Volume that is currently connected to the Instance
Make sure that no other Volumes are selected
Click the More… drop down list and select Click the More… drop down list and select Detach Volume
Uncheck the box selected and check the box next to the new Volume
Click the More… drop down list and select Click the More… drop down list and select Attach Volume
Select the Instance that you wish to change
Change the value in Device from xvdf  to /dev/sda1
Click Yes, Attach
Navigate to Instances and start your Instance
Once you are satisfied that the volume works, feel free to delete the Snapshot and old Volume if you like