Question

From the Amazon RDS FAQ Page
http://aws.amazon.com/rds/faqs/

“Depending on the size of storage requested, Amazon RDS automatically stripes across multiple EBS volumes to enhance IOPS performance”

What disk size do I need to request to trigger disk striping? I’ve only heard rumors of 300GB.

Answer 1

I had a conversation with upper management at AWS regarding this. Here is the direct answer provided by them.

You will realize improvements with RDS throughput by scaling storage as high as 500GB, and this effect starts at a level well under 100GB (ie: striping occurs at a far lower level than 300GB).
The most important factor in realizing this throughput potential is the instance class. Specifically, the following instance classes are considered High I/O instances:

m1.xlarge

m2.2xlarge

m2.4xlarge

These instances have large network bandwidth available to them, so the upgrade that you mentioned on stackoverflow (to the m2.2xlarge instance) was likely the main reason you saw a leap in throughput. If you stripe your current storage as high as 500GB, this will continue to increase. With provisioned IOPS support for RDS (PIOPS-announced last night), throughput will now scale linearly all the way to 1TB.

With PIOPS, the throughput rate you can expect is currently associated with the amount of allocated storage. For Oracle and MySQL databases, you will realize a very consistent 1,000 IOPS for each 100GB you allocate – resulting in a potential throughput max of 10K IOPS. The (current, temporary) downside is that you will need to unload/load data to migrate an existing app to the PIOPS RDS.