As your application grows, so does the need for storage. On AWS EC2 instances, running out of disk space can lead to app crashes, failed deployments, or a frozen system. But the good news? You can increase an EC2 volume in real-time without stopping the instance.

In this article, I’ll walk you through a real-world example, breaking it down into simple, actionable steps you can apply right away.

📸 The Scenario

Let’s say you SSH into your EC2 instance and run:

df -h

And you see something like this:

Filesystem      Size  Used Avail Use% Mounted on
/dev/root       6.8G  6.1G  682M  91% /
tmpfs           3.9G     0  3.9G   0% /dev/shm
/dev/xvda16    881M   76M  744M  10% /boot
/dev/xvda15    105M  6.1M   99M   6% /boot/efi

✅ /dev/root → This is your main Linux root filesystem.

⚠️ Problem: You’re at 91% usage — dangerously low on space.

If you don’t fix this, you may face:

Failed deployments
Database crashes
Frozen processes
Unreachable servers

⚙️ Step 1: Check which volume to resize

Find the volume attached to your EC2 instance. You’ll probably see it’s around 7–8 GB.

🚀 Step 2: Increase the volume size in AWS

Select the volume → Actions → Modify volume.
Change the size from, say, 7 GB → 20 GB.
Confirm and apply.

AWS will handle the resize behind the scenes. This usually takes a few seconds to a couple of minutes.

✅ Good news: Your EC2 instance keeps running — no downtime.

🖥️ Step 3: Verify the new disk size on EC2

SSH into your EC2 instance and run:

lsblk

You should now see the increased size at the block device level (e.g., /dev/xvda or /dev/root showing 20 GB).

🔧 Step 4: Expand the Linux filesystem

The Linux filesystem still thinks it’s using the old 7 GB. You need to tell it to use the full 20 GB.

First, check which filesystem you have:

df -T /

If you see:

ext4 → use resize2fs
xfs → use xfs_growfs

Run the right command:

For ext4:

sudo resize2fs /dev/root

For xfs:

sudo xfs_growfs /

✅ Step 5: Verify everything

df -h

Expected result:

Filesystem      Size  Used Avail Use% Mounted on
/dev/root       20G   6.1G  14G  31% /

🎉 Congratulations! Your disk space is expanded, and your server stays online.

💡 Bonus Tips

Always take an EBS snapshot before resizing, just in case.
Monitor disk space proactively using CloudWatch alarms.
Clean up old logs and temp files regularly to reduce unnecessary space usage.

📦 Final Takeaway

Increasing an EC2 volume is:
✅ Safe
✅ Zero downtime
✅ Easy to do with the right steps

The key part people miss? Expanding the Linux filesystem after resizing in AWS. Don’t skip that step!

How to Safely Increase EC2 Volume Size in Real-Time Without Downtime