I know this is probably a somewhat 'dumb' question :)

I have an AWS (small) instance and I just noticed that there is a ~150gb volume attached at /mnt, is this normal?

It kinda freaked me out, I was thinking maybe someone was trying to capture whatever I mount in /mnt, there is the entry in my fstab too (and I found that others have this by googling)... the entry is as follows

/dev/xvdb   /mnt    auto    defaults,nobootwait,comment=cloudconfig 0   2

I don't have any volumes this large in my AWS volumes section though. I was just trying to understand this and be sure that someone is not trying to 'get in'... as there are many attempts daily.


1 Answer 1


It's called ephemeral/instance storage (see http://aws.amazon.com/ec2/instance-types/). Basically, it's temporary storage space which is cleared on instance stop/termination. Suitable for temporary storage.

  • Thank you, I figured it was such but couldn't confirm... and didn't panic but wanted to know. I did all my development on the micro instance and just went production recently.
    – rhaag71
    Oct 9, 2012 at 15:44
  • 1
    Um, no, it exists still after reboot. If you terminate the instance or the instance dies on its own, that disk storage is lost, so back it up to S3.
    – user164042
    Oct 9, 2012 at 18:16
  • 2
    Ephemeral storage survives reboot, but is cleared on stop/start, terminate, and instance failure. I explain more differences between reboot and stop/start here: alestic.com/2011/09/ec2-reboot-stop-start Oct 9, 2012 at 21:33

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