How to resize the Root Disk on a running EBS Boot EC2 Instance

Solution Verified - Updated -

Environment

  • Red Hat Enterprise Linux (RHEL) 6.x

  • Amazon EC2

Issue

  • How to resize the Root Disk on a running EBS Boot EC2 Instance

Resolution

In the following example, we have a RHEL 6.2 EC2 running instance with 6GB root disk size. This is being extended to 15GB as per the requirement.

  • Check the Root Disk size of EC2 Instance and verify the size.

    [root@domU-12-31-39-0A-20-51 ~]# cat /etc/redhat-release 
Red Hat Enterprise Linux Server release 6.2 (Santiago)

[root@domU-12-31-39-0A-20-51 ~]# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/xvde1            5.7G  1.9G  3.7G  35% /
none                  3.7G     0  3.7G   0% /dev/shm

  • Login to AWS Console using your AWS sign up credentials. Now select the running instance under INSTANCES >> Instances and stop it.

  • After stopping the instance, go to ELASTIC BLOCK STORE >> Volumes. Identify the EBS volume for the instance and click option "Detach Volume" to detach it from the current instance.

  • On the same page click "Create Snapshot" to create Snapshot of the detached volume.

  • Go to ELASTIC BLOCK STORE >>Snapshots, select the created snapshot, choose the option "Create Volume", specify the required size of 15GB here and create it .
  • Go back to  ELASTIC BLOCK STORE >> Volumes where you will have the new Volume created, choose the new Volume and click on "Attach Volume", here you choose the instance and specify the Device to /dev/sda1 which is the boot EBS to be attached.
  • Go back to INSTANCES page and start the instance. Note that you will have a new public IP address/hostname.   (If you were using an elastic IP address, re-assign it to the instance.)

  • Connect the instance using ssh and resize the root file system to show up the new EBS volume.

    [root@domU-12-31-39-10-32-11 ~]# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/xvde1            5.7G  1.9G  3.7G  35% /
none                  3.7G     0  3.7G   0% /dev/shm

[root@domU-12-31-39-10-32-11 ~]# resize2fs /dev/xvde1
resize2fs 1.41.12 (17-May-2010)
Filesystem at /dev/xvde1 is mounted on /; on-line resizing required
old desc_blocks = 1, new_desc_blocks = 1
Performing an on-line resize of /dev/xvde1 to 3932160 (4k) blocks.
The filesystem on /dev/xvde1 is now 3932160 blocks long.

[root@domU-12-31-39-10-32-11 ~]# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/xvde1             15G  1.9G   13G  13% /
none                  3.7G     0  3.7G   0% /dev/shm
[root@domU-12-31-39-10-32-11 ~]#

Note: You can delete the old volume, but it is recommended to keep the snapshot for a while.

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