There's a new Amazon acronym to learn. RDS stands for Relational Database Service and it is the newest addition to Amazon's suite of web services. Unlike previous data services from Amazon such as SimpleDB, RDS is relational (our profiles for the SimpleDB API and new RDS API). In fact, it's a MySQL 5.1 instance but the main difference is that it is hosted on a virtual server instance in Amazon's data center. And it can expand and contract as needed, programmatically. Like the Amazon APIs before it, RDS was built to provide developers access to Amazon's infrastructure, with pay-as-you-go pricing based on your usage.
Amazon's announcement post explains a bit more:
Using RDS APIs or the command-line tools, you can access the full capabilities of a complete, self-contained MySQL 5.1 database instance in a matter of minutes. You can scale the processing power and storage space as needed with a single API call and you can initiate fully consistent database snapshots at any time.
The service is currently in beta. Each account will be limited to 20 databases during that period, but each can store up to one terabyte of data. That's a lot of tweets and status messages.
There are fees, of course. Storage costs 10 cents per GB per month, based on the total amount allocated. Hourly usage is charged based on the size of the database instance and ranges from 11 cents per hour up to $3.10 per hour for 68 GB of RAM, a hefty database. There is also a 10 cent fee for every million I/O requests.
Om Malik says Amazon is wooing corporate customers:
Relational databases are hard to maintain, and doing so eats up a lot of corporations' time. Nor do they scale easily, which means that Amazon may have built a compelling product for enterprise customers seeking to move to the cloud.
Indeed, savings on servers could be not nearly as important as saving employee time. Or, unfortunately, companies could look to save an employee or two if some database administration becomes automated.
Look for this service to also be popular with small, data-centric startups. Much as Amazon S3 (our Amazon S3 API profile) has been used by many--from no-names to Twitter--for storing profile images and other files in the cloud, RDS could be the next step in sequence.