|Consolidation of Windows AMIs||
Amazon EC2 no longer differentiates between Amazon EC2 running Windows and Amazon EC2 running Windows with Authentication Services. New and existing Windows instances can now run Authentication Services, such as LDAP and Kerberos, at no additional charge. Additionally, any currently running Windows with Authentication Services instances are now charged the same price as Windows instances.
Existing Windows AMIs will be removed starting October 15. If you need the current version of a Windows AMI, please rebundle your own copy of it.
|Windows Reserved Instances||Reserved Instances are not currently available for Windows.|
|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 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 is currently no support for volume attachment to devices beyond /dev/sdp on instances running Linux/UNIX and xvdp on instances running Windows.|
|Security group limitation||AuthorizeSecurityGroupIngress does not allow port ranges for group grants when using the command-line tools or the Query API. This is only supported through the SOAP API.|
|Instance limit||New users 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 http://aws.amazon.com/contact-us/ec2-request/.|