AWS Guides: How to resize a EC2 Windows EBS Volume

The following guide will help you resize an EBS volume on a Windows instance inside EC2 on AWS. The task can be a little daunting but is quite easy once you have done it the first time. Remember this guide only helps with increasing the size of the EBS volume not decrease it. Please be sure to also check out my guide on how to increase the root volume size of an Ec2 Linux Volume.

Step 1: Stop the instance that you are going to perform the volume resize on. (Note: This step is recommended but not required).

Step 2: Create a snapshot of the volume attached to the instance. This can be accomplished by navigating to the EC2 section of the AWS Console and selecting volumes, the ‘attachment information’ column will show which instance the volume is attached to. Once you find the volume, right click and select create snapshot. The details of the snapshot can be whatever you want.

Step 3: Navigate to the snapshot section of the EC2 console on the left side. Once the snapshot creation completes (Note: this can take minutes to hours depending on the size of the volume). Right click on the snapshot that you just created and select ‘create volume’. Make sure you create the volume in the same availability zone as the instance. On the next screen you can specify a larger volume size than previously, for example if the original volume was 30gb you can specify 100gb now (Note: You cannot specify a volume size smaller than the original snapshot size).


Step 4: Once the new volume is created, detach the original volume from the instance and attach the new volume that was created. (Note: Make sure you mount the volume on the same mount point as it was originally notated by ‘Device’ in the picture below). The root volume is usually /dev/sda1.

Step 5: Start the instance.

Step 6: The new volume size will not be reflected immediately inside the Windows instance so you will have to do one more thing. Connect to your Windows instance with Remote Desktop and open the start menu. In the run menu or the bottom of the start menu on newer versions of Windows type ‘Diskmgmt.msc’ and press enter. On the Disk Management window you want to find the drive you want to resize this is usually the C: drive for the root volume. Right click on the drive and say Extend, follow the wizard and voila you have resized your volume on EC2.

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