Release: Amazon EC2 on 2011-03-15

Release Notes>Amazon EC2>Release: Amazon EC2 on 2011 03 15
Support for Windows Server 2008 R2


Submitted By: Francis@AWS
Release Date: March 15, 2011 7:00 AM GMT
Latest Version: 2011-01-01
Latest WSDL:
Created On: March 16, 2011 4:49 AM GMT
Last Updated: March 16, 2011 4:49 AM GMT

New Features

Windows Server 2008 R2 Support Amazon EC2 now provides you with several pre-configured Windows Server 2008 R2 AMIs. All of these AMIs are immediately available for use in every Region and in most 64-bit instance types, excluding t1.micro and HPC families. The AMIs will support multiple languages.

Support for VPC is not included at launch, but will be added shortly. For more information, please visit the page Amazon EC2 Running Microsoft Windows Server & SQL Server.

Known Issues

Current Limitations for VM Import Following are current limitations of VM Import:
  • The following types of images currently cannot be imported into Amazon EC2:
    • VMware Workstation VMDK images
    • Encrypted, compressed, or read-only images
    • Started or suspended images
    • Linked clones
    • Images with multiple virtual disks

  • When you import a disk image to an Amazon EC2 instance, the instance appears in the AWS Management Console before the conversion process finishes. To determine when the process is complete and the instance is available to use, use the ec2-describe-conversion-tasks command.
Current Limitations for Cluster Instances Following are current limitations of cluster compute and cluster GPU instances:
  • Only the US-East (Northern Virginia) Region supports cluster instances
  • Microsoft Windows Server is not supported
  • Spot Instance requests are not supported
  • Amazon Virtual Private Cloud is not supported
  • Amazon DevPay is not supported
Current Limitations for Cluster Placement Groups Following are current limitations of cluster placement groups:
  • Reserved Instances are not currently available within a cluster placement group
Current Limitations for Tags and Filters You currently cannot tag the following resources:
  • Elastic IP addresses
  • Key pairs
  • Placement groups
You can currently filter your resources in the AWS Management Console by tag, but not by the other filters that are available to use with Describe* actions through the command line tools or API.
Current Limitations for Micro Instances Following are current limitations of micro instances:
  • Amazon Virtual Private Cloud is not supported
  • Amazon Elastic MapReduce is not supported
  • Amazon DevPay is not supported
Instance Clock Drift Some instances (Windows instances in particular) can experience a system clock drift. The issue appears to be more severe in t1.micro Windows instances that run CPU-intensive workloads. If your application is sensitive to time drift, consider using other instance types until a resolution is available.
Setting the TCP_MAXSEG Socket Option The 2.6.18-164.15.1 kernel used in the CentOS 5.4 reference AMI (ami-7ea24a17) contains a known issue: Setting the TCP_MAXSEG socket option on TCP sockets to certain values (e.g., 1500) causes the kernel to generate TCP Segmentation Offload (TSO) packets with invalid sizes that the NIC driver then drops. The impact is significantly lower network throughput. As a workaround, don't set this socket option and let the kernel use the default settings to handle segmentation and Path Maximum Transmission Unit (PMTU) discovery.
Query Version of ModifyInstanceAttribute The ModifyInstanceAttribute action currently does not allow you to modify the block device mapping for the instance.
Paid AMIs Backed by Amazon EBS Amazon EBS-backed AMIs are not currently supported by Amazon DevPay.
Windows AMI launch times Windows AMIs take longer to launch than Linux/UNIX instances due to larger AMI sizes and multiple reboots.
Windows AMI sizes Installing software on Amazon S3-backed Windows AMIs can cause them to become large and easily reach the 10 GB limit. Before bundling, check the size of the C:\ volume.
Limitation on drive mapping There are limitations on devices available for storage attachment. For more information, go to How to Attach the Volume to an Instance in the Amazon Elastic Compute Cloud User Guide.
Instance limit New AWS accounts are limited to a maximum of 20 concurrent instances, but many of our customers use hundreds or thousands of instances. If you need a higher limit, go to
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