When you launch an Amazon EC2 instance, you define an Amazon EBS volume size. However, you may eventually need more disk space later for some reason. In this blog post, I will demonstrate an example of how you can increase the root volume size of an EC2 Linux instance.
There are three components of this operation:
- AWS Elastic Block Storage (EBS) volumes attached as block devices to our EC2 instance, such as
- Partitions on block devices, such as
- Mounted filesystem on the operating system such as
"/dev/xvda1" mounted on "/".
Checking the Block Devices and the Filesystem on Your EC2 Instance
First of all, let’s connect to our EC2 instance using SSH. For demonstration, I will be using a
t2.micro type of Amazon EC2 instance backed by an 8 GB EBS volume initially and running Ubuntu 16.04LTS operating system.
After connecting to our EC2 instance, let’s list its block devices available:
Here, we see that there are 8GB on the xvda block device, and all 8GB is allocated to the xvda1 partition as expected.
Then, let’s display the amount of disk space used and available on the Linux filesystem.
As can be seen, we have a 7.7 GB disk space available on
/dev/xvda1, which we will increase by 2 GB. AWS automatically allocated the remaining, nearly 0.3 GB, to the
One more thing to go, we need to determine whether the disk use
xfs file system:
So, we checked the initial state of our EC2 instance. Next, let’s continue by resizing its volume using AWS Management Console.
Modifying Your EBS volume on AWS Management Console
On our Amazon EC2 dashboard, let’s click
Volumes under the
ELASTIC BLOCK STORE section on the left. Here, we need to select the volume attached to our instance and click
Modify from the
Actions menu. You can see the screenshot below.
Let’s increase the volume size on the window opened. As an example, I will resize my EBS volume to 10GB.
Modify, AWS will display an approval window to avoid unintended actions; click
Yes on this window to continue. After that, a success message will be displayed for the start of the EBS volume resize operation, which you can ignore by clicking
After getting the volume increase request, AWS will resize the EBS volume in seconds. You will need to refresh the page a few times to see that the process finished successfully.
We resized our EBS volume successfully. However, we need to extend the OS file system on our EC2 instance for the new EBS volume size to take effect.
Extending the OS Filesystem (ext3, ext4) on Your EC2 Instance
Please remember that we initially listed the block devices on our EC2 instance and saw that all 8GB of xvda was allocated to the xvda1 partition. Now, let’s list them once more after resizing our EBS volume to see what it displays:
As you see, the size of the xvda block increased from 8 GB to 10 GB; but the
xvda1 partition uses only 8 GB of it. We should allocate all 10 GB to
xvda1, right? We can do this using the
growpart command as our filesystem is
Now, let’s confirm that all the storage is allocated to the
xvda1 partition by listing the block devices again:
OK. We increased block storage, but we also need to resize the filesystem to be able to use it:
Let’s confirm the operation by redisplaying the filesystem disk space usage.
As you see, the size of the
/dev/xvda1 partition became 9.7 GB with a net 2 GB increase. Hence, our EBS volume resize operation is successful.
In the lifetime of our EBS backed EC2 instances, we may need to increase the root or other EBS volumes of them. In this blog post, I demonstrated to achieve this on an Ubuntu EC2 instance with the ext4 filesystem. For ext3, the process is also the same. If your instance runs Amazon Linux or Centos operating systems with ext3 or ext4 filesystems, you can apply the same method here.
However, if your filesystem is
xfs, you need to do the filesystem extension using the
xfsprog command. You can find the link for its details on the AWS documentation in the references section below.
Thanks for reading!