AWS EBS Performance

Here is a very good presentation on Amazon EBS performance from reInvent in 2013:
http://www.slideshare.net/AmazonWebServices/ebs-webinarfinal

EC2 EBS optimized instances throughput

EC2 EBS-Optimized Instances are listed here:

http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/EBSOptimized.html

It is important to understand the maximum throughput in MB/s and maximum 16 KB IOPS when architecting Oracle databases on AWS.  

Oracle Database size and network throughput : IOPS and network throughput

When configuring an Oracle Database on AWS EC2, you need to consider both storage (EBS) IOPS and network throughput.   With PIOPS, you can achieve up to 4K IOPS per EBS volumes.  However, the EC2 instances (assuming EBS optimized or 10 Gbps cluster compute) can be a potential bottle neck.  For example, the m2.2xlarge instance type has a maximum throughput of 0.5Gb.  Which means this instance type is limited to approximately 3750 * 16 KiB IOPS. Therefore, one 4K PIOPS volume would start to saturate the network.   Take into account the IOPS and instance network throughput when designing your Oracle Database on AWS EC2.

EC2 EBS Optimized Instances

Because Oracle databases are typically terabytes in size and required 1000's of IOPS, you will typically use EBS PIOPS volumes with EBS-optimized EC2 instances.   This leads the often asked question of "What does EBS optimized EC2 instances really mean?"  The short answer is that storage pipe to the EBS (PIOPS) volume is dedicated and does not compete with network traffic like it does in a non EBS-optimized instance.  A more detailed answer can be found here:
http://perspectives.mvdirona.com/2012/08/01/EBSProvisionedIOPSOptimizedInstanceTypes.aspx

On a related note, additional instance types now offered EBS Optimized functionality: http://aws.amazon.com/about-aws/whats-new/2013/03/19/announcing-ebs-optimized-support-for-additional-instance-types/