Resize AWS EBS without Rebooting

There’s no need to stop instance and detach EBS volume to resize it anymore!

Starting 13-Feb-2017 Amazon announced: “Amazon EBS Update — New Elastic Volumes Change Everything

The process works even if the volume to extend is the root volume of running instance!


Say we want to increase boot drive of Ubuntu from 8G up to 16G “on-the-fly”.

step-1) login into AWS web console -> EBS -> right mouse click on the one you wish to resize -> “Modify Volume” -> change “Size” field and click [Modify] button


step-2) ssh into the instance and resize the partition:

let’s list block devices attached to our box:

lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
xvda 202:0 0 16G 0 disk
└─xvda1 202:1 0 8G 0 part /

As you can see /dev/xvda1 is still 8 GiB partition on a 16 GiB device and there are no other partitions on the volume. Let’s use “growpart” to resize 8G partition up to 16G:

# install "cloud-guest-utils" if it is not installed already
apt install cloud-guest-utils
# resize partition
growpart /dev/xvda 1

Let’s check the result (you can see /dev/xvda1 is now 16G):

lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
xvda 202:0 0 16G 0 disk
└─xvda1 202:1 0 16G 0 part /

Lots of SO answers suggest to use fdisk with delete / recreate partitions, which is nasty, risky, error-prone process especially when we change boot drive.


step-3) resize file system to grow all the way to fully use new partition space

# Check before resizing ("Avail" shows 1.1G):
df -h
Filesystem Size Used Avail Use% Mounted on
/dev/xvda1 7.8G 6.3G 1.1G 86% /
# resize filesystem
resize2fs /dev/xvda1
# Check after resizing ("Avail" now shows 8.7G!-):
df -h
Filesystem Size Used Avail Use% Mounted on
/dev/xvda1 16G 6.3G 8.7G 42% /

So we have zero downtime and lots of new space to use.
Enjoy!

Originally posted on SO http://stackoverflow.com/questions/11014584/ec2-cant-resize-volume-after-increasing-size

By http://stackoverflow.com/users/7022062/dmitry-shevkoplyas

Thanks Dmitry Shevkoplyas!