Feature Guide: Amazon EC2 High-CPU Instance Types

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Amazon EC2 now provides High-CPU instance types.


Submitted By: Bruce@AWS
AWS Products Used: Amazon EC2
Created On: May 29, 2008 4:22 PM GMT
Last Updated: September 21, 2008 9:59 PM GMT

Available Amazon EC2 High-CPU Instance Types

Amazon EC2 now provides High-CPU instance types. High-CPU instance types have a proportionately higher ratio of CPU to memory and are well suited for compute-intensive applications.

There are two new High-CPU instance types: c1.medium and c1.xlarge.

High-CPU Medium Instance

1.7 GB memory
5 EC2 Compute Units (2 virtual core with 2.5 EC2 Compute Unit each)
350 GB instance storage (340 GB plus 10 GB root partition)
32-bit platform
I/O Performance: Moderate
Instance Type name: c1.medium (used in EC2 APIs)
Price: $0.20 per instance hour

High-CPU Extra Large Instance

7 GB memory
20 EC2 Compute Units (8 virtual cores with 2.5 EC2 Compute Units each)
1,690 GB instance storage (4 x 420 GB plus 10 GB root partition)
64-bit platform
I/O Performance: High
Instance Type name: c1.xlarge (used in EC2 APIs)
Price: $0.80 per instance hour

For more information about Amazon EC2 instance types, how we measure compute resources, and
how we measure I/O performance, go to http://www.amazon.com/b?ie=UTF8&node=370375011


Before you begin, make sure you are using the right versions of our WSDL, API Tools, and API:

  • WSDL and API version: 2008-02-01 or later
  • API Tools: 1.3-19403 or later

Note: You can check version information using the ec2ver command.

Finding the Amazon Public 64-bit AMI

The large and extra large instances are 64-bit which require 64-bit AMIs. We provide a public 64-bit AMI that you can find by searching for public AMIs owned by Amazon with “x86_64” in the manifest path.

This example shows how to use the ec2dim command and grep to locate the 64-bit public AMI:       

ec2dim -o amazon | grep  x86_64
IMAGE   <ami-id>   ec2-public-images/fedora-core6-base-x86_64.manifest.xml 
amazon    available   public 

The original instance type (now called the small instance or m1.small), no change is required. It is a 32-bit instance; you can launch your previous 32-bit AMIs without changes.

Launching New Instance Types

We strongly recommend using the 2.6.18 Xen stock kernel with the c1.medium and c1.xlarge instances. Although the default Amazon EC2 kernels will work, the new kernels provide greater stability and performance for these instance types. For more information about kernels, refer to the Amazon Elastic Compute Cloud Developer Guide.

This example finds 2.6.18 Xen stock kernels:

ec2dim -o amazon | grep 2.6.18
IMAGE   aki-9b00e5f2     ec2-public-images/vmlinuz-2.6.18-xenU-ec2-v1.0.i386.aki.manifest.xml    amazon   available       public          i386    kernel
IMAGE   aki-9800e5f1     ec2-public-images/vmlinuz-2.6.18-xenU-ec2-v1.0.x86_64.aki.manifest.xml  amazon   available       public          x86_64  kernel

This example starts a High-CPU extra large instance, using the 32-bit aki-9800e5f1 kernel:

ec2run  <ami-id> --instance-type c1.xlarge -k <keypair> --kernel  aki-9800e5f1

This example starts a High-CPU medium instance, using the 32-bit aki-9b00e5f2 kernel:

ec2run <ami-id>  --instance-type c1.medium -k <keypair> --kernel aki-9b00e5f2

Describing Instances

The following is an example of output from the DescribeInstances response, which displays the type of instance that is running.

$ ec2din
RESERVATION     r-5824c031      416161254515    default
INSTANCE        i-edb05684      ami-b98d68d0    ec2-72-44-47-95.z-3.compute-1.amazonaws.com      domU-12-31-35-00-3C-81.z-2.compute-1.internal   running    0   c1.xlarge   2007-07-13T15:13:36+0000
RESERVATION     r-46de3a2f      416161254515    default
INSTANCE        i-85af49ec      ami-2bb65342    ec2-72-44-56-99.z-3.compute-1.amazonaws.com      domU-12-31-36-00-34-C3.z-1.compute-1.internal   running    0   m1.small   2007-08-10T16:00:09+0000

Instance Storage

Instance storage on the new instance types is exposed as follows:

  • /dev/sda (formatted and mounted as root (/) on all instance types)
  • /dev/sdb (/mnt on High-CPU extra large instance types)
  • /dev/sdc (on High-CPU extra large instance types, not mounted)
  • /dev/sdd (on High-CPU extra large instance types, not mounted)
  • /dev/sde (on High-CPU extra large instance types, not mounted)

Instance storage is subject to the same constraints as the ephemeral store of the original instance. The disk contents will survive a reboot of the instance (or the host machine), but will be lost when the instance is terminated.

For more information, see the "Disk Performance Optimization" section of the Amazon EC2 Developer Guide.

Obtaining the Instance Type via Instance Meta-Data

The instance type is exposed as part of the instance meta-data. It can be queried from within an instance as follows:


Bundling Instances

To bundle instances, please use our new AMI Tools. These tools can bundle any of the available instance types.

Previous versions of the tool chose a fixed fstab file. The new tools pick the appropriate fstab file for the instance type or allow you to override the file. The new tools can bundle 64-bit or 32-bit AMIs.


Please review the Technical FAQs section of the Amazon Elastic Compute Cloud Developer Guide, especially the FAQs in the “Instance Types” section.

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