|Volume Status Checks||
Volume status provides information about the I/O (read/write) capability of your Amazon Elastic Block Store (Amazon EBS) volume. The status check lets you know when an EBS volume's data is potentially inconsistent.
|A New API Version||
The new API version 2012-03-01 introduces four new API actions to support volume status checks: DescribeVolumeStatus, DescribeVolumeAttribute, EnableVolumeIO, and ModifyVolumeAttribute.
To view earlier EC2 Release Notes please see http://aws.amazon.com/releasenotes/Amazon EC2.
|Elastic Network Interfaces||Warm attachment (when the instance is stopped) and Hot attachment (when the instance is running) of network interfaces to Windows Server 2003 instances isn't supported at this time.|
|Current Limitations for VM Import||
Following are current limitations of VM Import:
|Current Limitations for Cluster Instances||Following are current limitations of cluster compute and cluster GPU instances:
|Current Limitations for Cluster Placement Groups||Following are current limitations of cluster placement groups:
|Current Limitations for Tags and Filters||You currently cannot tag the following resources:
|Current Limitations for Micro Instances||Following are current limitations of micro instances:
|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 Attaching 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 Request to Increase Amazon EC2 Instance Limit (http://aws.amazon.com/contact-us/ec2-request).|