Home / server / Questions / 155193
Accepted
001
Asked: 2010-06-27 18:25:11 +0800 CST

Amazon ec2 - how to setup?

  • 772

Everytime I launch a new large ec2 instance, I get 30GB of storage,

Did I do something wrong? shouldn't i get 850GB?

See instance type http://aws.amazon.com/ec2/instance-types/

Large Instance

7.5 GB memory
4 EC2 Compute Units (2 virtual cores with 2 EC2 Compute Units each)
850 GB instance storage (2×420 GB plus 10 GB root partition)
64-bit platform
I/O Performance: High
API name: m1.large

p.s I launch my instances with AWS Management Console wizard.

amazon-ec2 amazon-web-services

2 Answers

  1. Best Answer

    The root partition of an EC2 instance is taken directly from the AMI you're launching with, and it is the same size as the AMI itself. If you have a 30GB AMI, you get a 30GB root partition.

    The "instance storage" described on that page comes as one or more separate scratch partitions. I don't have a running instance in front of me, but the partitions will typically show up as /dev/sdb, /dev/sdc, etc. I believe that the first is formatted as ext3 and mounted at /mnt; you have to mount (and possibly format) the other partitions yourself.

    Edit: Here's what I get if I start up a Large instance using the ami-fd4aa494 AMI from http://uec-images.ubuntu.com/releases/lucid/release/.

    ubuntu@ip-10-212-181-187:~$ mount | tail -n 1
/dev/sdb on /mnt type ext3 (rw)
ubuntu@ip-10-212-181-187:~$ df -h | tail -n 1
/dev/sdb              414G  199M  393G   1% /mnt
ubuntu@ip-10-212-181-187:~$ sudo blockdev --getsize64 /dev/sdb
450934865920
ubuntu@ip-10-212-181-187:~$ sudo blockdev --getsize64 /dev/sdc
450934865920
    • 5

  2. The 850GB you reference is called ephemeral storage (or instance store), and the size depends on the instance type. It gets destroyed if you shut down your instance, while EBS volumes do not ( you didn't specify which type of boot partition you are using: ephemeral or EBS).

    The image itself determines how much of the 850GB instance store is mounted and to what device. If only 30GB shows up, that's because the image was created with that storage mounted.

    You can mount the rest of the storage by listing the scsi devices like ls -l /dev/sd* Then partition the ephemeral device using fdisk, then format it with mkfs, then mount it with mount.

    • 4