Running out of disk space EC2
I ran into some issues with my EC2 micro instance and had to terminate it and create a new one in its place. But it seems even though the old instance is no longer visible in the list, it is still using up some space on my disk. My df -h is listed below:
Filesystem Size Used Avail Use%
/dev/xvda1 7.8G 7.0G 719M 91% /
When I go to the EC22 console I see there are 3 volumes each 8gb in the list. One of them is attached (/dev/xvda) and this one is showing as "in-use". The other 2 are simply showing as "Available"
Is the terminated instance really using up my disk space? If yes, how to free it up?
Answer
Amazon Elastic Block Storage (EBS) is a service that provides virtual disks for use with Amazon EC2. It is network-attached storage that persists even when an EC2 instance is stopped or terminated.
When launching an Amazon EC2 instance, a boot volume is automatically attached to the instance. The contents of the boot volume is copied from an Amazon Machine Image (AMI), which can be chosen from a pre-populated list (including the ability to create your own AMI).
When an Amazon EC2 instance is Stopped, all EBS volumes remain attached to the instance. This allows the instance to be Started with the same configuration as when it was stopped.
When an Amazon EC2 instance is Terminated, EBS volumes might or might not be deleted, based upon the Delete on Termination setting of each volume:
By default, boot volumes are deleted when an instance is terminated. This is because the volume was originally just a copy of an AMI, so there is unlikely to be any important data on the volume. (Hint: Don't store data on a boot volume.)
Additional volumes default to "do not delete on termination", on the assumption that they contain data that should be retained. When the instance is terminated, these volumes will remain in an Available state, ready to be attached to another instance.
So, if you do not require any content on your remaining EBS volumes, simply delete them. In future, when launching instances, keep an eye on the Delete on Termination setting to make the clean-up process simpler.
Please note that the df -h command is only showing currently-attached volumes. It is not showing the volumes in Available state, since they are not visible to that instance. The concept of "Disk Space" typical refers to the space within an EBS volume, while "EBS Storage" refers to the volumes themselves. So, the 7GB of the volume that is used is related to that specific (boot) volume.
If you are running out of space on an EBS volume, see: Expanding the Storage Space of an EBS Volume on Linux. Expanding the volume involves:
- Creating a snapshot
- Creating a new (bigger) volume from the snapshot
- Swapping the disks (requiring a Stop/Start if you are swapping a boot volume)