[ec2] partition thinking

[Eric Hammond]

Micah:

Amazon EC2 only allows a max of 10GB on the root partition.  There's no
way to make it bigger and no reason to make it smaller.  (You can always
use symlinks or mount --bind to make it look like specific directories
are bigger, but they aren't really on the root partition and you can
never bundle more than 10GB in an image.)


As far as ephemeral storage goes, Linux m1.large instances always start
with /dev/sdb formatted and mounted as /mnt, and /dev/sdc available but
not formatted or mounted.  This is not specific to the Alestic.com images.

It is up to you to format and mount /dev/sdc if you need all the
ephemeral storage provided.  I suppose some images could format and
mount the extra ephemeral storage, but this would be on top of the EC2
policy.

The xlarge instances have four devices for ephemeral storage.  If you
want it as contiguous space, you can RAID them together.

Here's some EC2 documentation which describes the various storage
layouts in a confusing way:

  http://ec2storage.notlong.com

--
Eric Hammond
ehammond at thinksome.com



Micah Walter wrote:
> Hi Everyone,
> I'm sort of curious about the thinking behind the partition structure for these AMIs. Is there are strong reason for creating a 10 gig partition for the system and then leaving the rest to /mnt? 
> 
> I'm still a little new to Ubuntu, so maybe this is the industry standard.... but I would really like to hear what others thought.
> 
> Also, I noticed on some of the Alestic images, that when starting a large instance I only have about half of the "advertised" disk space. According to the AWS docs for a m1.large I should have had 850 gig, but I only had about 450 when doing a df -h.
> 
> -micah
>