HVM and PVM : Oracle AMIs

AWS AMIs are either Para Virtual Machine (PVM) or Hardware Virtual Machine (HVM) images. All of the AMIs from Oracle are currently only PVM-based. Therefore, they will not run on cluster compute or i2 instance types.

More information on HVM-based instances types:
http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/using_cluster_computing.html#concepts_cluster_compute_hvmAMI
http://aws.amazon.com/ec2/faqs/#Does_use_of_Cluster_Compute_Instances_differ_from_other_Amazon_EC2_instance_types

Currently, the new i2 instance types are HVM only:
http://aws.amazon.com/about-aws/whats-new/2013/12/19/announcing-the-next-generation-of-amazon-ec2-high-i/o-instance/

More on HVM and PVM can be found here:
http://serverfault.com/questions/222010/difference-between-xen-pv-xen-kvm-and-hvm

If you are looking to run Oracle solutions on Oracle Enterprise Linux and require more then 68 GB of memory, you would have to run on hs1.8xlarge (117 GiB) as all other instance types with more then 68 GB are HVM. See more here: http://aws.amazon.com/amazon-linux-ami/instance-type-matrix/

Oracle Database on SSD

New options for running the Oracle Database on EC2 using SSD storage for your database. The I2 instances feature the latest generation of Intel Ivy Bridge processors - each virtual CPU (vCPU) is a hardware hyperthread from an Intel Xeon E5-2670 v2 (Ivy Bridge) processor. I2 instances are available in four sizes as listed in the table below. Instance Type vCPUs ECU Rating Memory (GiB) Instance Storage SSD (GB) Note           i2.xlarge 4 14 30.5 1 x 800 800 GB of SSD i2.2xlarge 8 27 61 2 x 800 1.6 TB of SSD i2.4xlarge 16 53 122 4 x 800 3.2 TB of SSD. hi.4xlarge with 2 TB  of SSD was previously largest SSD instance type i2.8xlarge 32 104 244 8 x 800 6.4 TB of SSD The i2.8xlarge instance size is capable of providing over 365,000 4 kilobyte (KB) random read IOPS and over 315,000 4 KB random write IOPS.   Great for Oracle databases that have high IO requirements.  This document has more on configuring Oracle Databases on EC2 and using SSD based instances : http://cloudconclave.blogspot.com/2013/11/aws-database-reference-implementation.html