|New Instance Type||Amazon EC2 now supports a new instance type: Cluster GPU (cg1.4xlarge). This type is available only in the US-East (Northern Virginia) Region.
For more information about the new instance type, go to:
A CentOS 5.5 reference AMI for cluster instances is available: ami-42a2532b. You can customize an instance of the reference AMI and then create your own image.
The reference AMI includes the NVIDIA driver and CUDA toolkit, which enable the GPUs. For more details about the AMI, go to Cluster Instance Concepts.
|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:
|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.|
|Can't Use ModifyInstanceAttribute to Modify Instance's Block Device Mapping||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 http://aws.amazon.com/contact-us/ec2-request.|