|M3 Instance Types||
The M3 standard instance types are the latest addition to the Amazon EC2 instance families. The other EC2 instance families include: M1 standard, high-memory, high-CPU, cluster compute, cluster GPU, high I/O, and t1.micro.
While both M1 and M3 standard instances have memory-to-CPU ratios suitable for most general-purpose applications, M3 standard instances provide higher absolute CPU performance for CPU-intensive applications, such as batch processing applications and web servers.
When choosing instance types, consider the resource utilization of your application so that you can select the optimal instance family and size. For more information, see Instance Families and Types.
To view earlier EC2 Release Notes please see http://aws.amazon.com/releasenotes/Amazon EC2.
|Current Limitations for VM Import||
Following are current limitations of VM Import:
|Current Limitations for M3 Standard Instances||Following are current limitations of m3.xlarge and m3.2xlarge instances:
|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 (of which 2 may be CG1 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).|