I have several sites with very high traffic - all hosted on Heroku and all of which access a db.m1.large mySQL Amazon RDS instance - and would like to know if there would be a performance benefit in upgrading to an instance with more processing power or memory. The screenshot below shows what the metrics look like. Is this the right way of analyzing the issue - and if so, does it indicate any need to upgrade?
You're Read IOPS seem pretty spikey on a regular basis, but Write IOPS are still within the expected range for Standard EBS (http://aws.amazon.com/ec2/faqs/#What_kind_of_performance_can_I_expect_from_Amazon_EBS_volumes), depending on how much storage you're allocating for the instance.
Given that, you might benefit from a Read Replica to scale out those reads, if this is MySQL. Additionally, leveraging the query cache (http://dev.mysql.com/doc/refman/5.5/en/query-cache.html) for in-memory result set caching would reduce Read IOPS and CPU utilization for some queries, or tuning the InnoDB Buffer Pool (http://dev.mysql.com/doc/refman/5.5/en/innodb-buffer-pool.html) to cache rowsets in memory can improve Read IOPS by itself.
