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I have a running AWS EC2 instance (Ubuntu 12.04.4 LTS). When I ssh into that instance and do a 'df -h', I see the following:

Filesystem      Size  Used Avail Use% Mounted on
/dev/xvda1       99G   75G   19G  80% /
udev            1.9G  8.0K  1.9G   1% /dev
tmpfs           378M  172K  378M   1% /run
none            5.0M     0  5.0M   0% /run/lock
none            1.9G     0  1.9G   0% /run/shm
/dev/xvda2      394G  199M  374G   1% /mnt

Please note the last line in the above output, which is

/dev/xvda2      394G  199M  374G   1% /mnt

Now here is my confusion. It shows 394G of disk that is mounted in the directory /mnt. But in my effort in trying to figure out where this volume is coming from, I seem to be going no where. In order to find out where this volume is coming from, I logged into my AWS EC2 Console and then looked at the list of attached volumes that I have in there. I assume the above volume is attached, given it shows up on an EC2 instance. But when I look at the list of attached volumes, nowhere do I see a volume of around such a big size i.e. 394G. All I see is something like the following:

vol-<volumeid> 8 GiB ...
vol-<volumeid> 8 GiB ...
vol-<volumeid> 8 GiB ...
vol-<volumeid> 100 GiB ...
vol-<volumeid> 10 GiB ...
vol-<volumeid> 10 GiB ...
vol-<volumeid> 10 GiB ...

None of these volumes add up to approximately 400 GiB

Also when I look at the EC2 instance itself, I see the following disks mounted on this instance:

Root device type ebs
Termination protection False
Root device /dev/sda1
Lifecycle normal
Block devices /dev/sda1

All I see is two /dev/sda1 entries (how come?) and none like /dev/xvda2.

So how do I now identify where the /dev/xvda2 is coming from, identify it on the AWS Console and then figure out how to delete it or manipulate it etc. Hope my question is making sense. If not, please let me know what additional information I need to provide to solve this.

Thanks.

  • wow, someone added an answer (suggesting that this is an ephemeral volume etc.), and my attempt to comment on it failed as they removed it immediately. – jark Jun 20 '14 at 21:06
  • That was me - after looking at your df output more carefully, realized that the ~400G vol was xvda2, not a separate volume. – EEAA Jun 20 '14 at 21:12
  • @EEAA your answer is actually correct. – Mark Wagner Jun 20 '14 at 23:18
  • @jark what is the instance type? – Mark Wagner Jun 20 '14 at 23:19
  • @jark - in that case, the answer has been un-deleted. :) – EEAA Jun 21 '14 at 0:39
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/dev/xvda1       99G   75G   19G  80% /

This is your "root" EBS volume. It is one of the vols you can see on the AWS admin console.

/dev/xvda2      394G  199M  374G   1% /mnt

This is your "ephemeral volume". It's local to the host your machine is running on, and will be lost if your server is stopped. This space is useful for working space, caching, etc, for storing data that you don't mind losing if the instance tanks. This volume cannot be manipulated in any way other than choosing to attach (or not) upon starting an instance.

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