| 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:
- All cluster instance types are available in the US East (N. Virginia) Region.
In addition, the cc2.8xlarge instance type is also available in the EU (Ireland) and US West (Oregon) Regions.
- 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
|
| 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). |
Release: Amazon EC2 on 2012-07-31
