I have a Java program and PHP website I plan to run on my Amazon EC2 instance with an EBS volume. The program writes to and reads from a database. The website only reads from the same database.
On AWS you pay for the amount of IOPS (I/O requests Per Second) to the volume. Which database has the least IOPS? Also, can SQLite handle queries from both the program and website simultaneously?
The amount of IO is going to depend a lot on how you have MySQL configured and how your application uses the database. Caching, log file sizes, database engine, transactions, etc. will all affect how much IO you do. In other words, it’s probably not possible to predict in advance although I’d guess that SQLite would have more disk IO simply because the database file has to be opened and closed all the time while MySQL writes and reads (in particular) can be cached in memory by MySQL itself.
This site, Estimating I/O requests, has a neat method for calculating your actual IO and using that to estimate your EBS costs. You could run your application on a test system under simulated loads and use this technique to measure the difference in IO between a MySQL solution and a SQLite solution.
In practice, it may not really matter. The cost is $0.10 per million IO requests. On a medium-traffic e-commerce site with heavy database access we were doing about 315 million IO requests per month, or $31. This was negligible compared to the EC2, storage, and bandwidth costs which ran into the thousands. You can use the AWS cost calculator to plug in estimates and calculate all of your AWS costs.
You should also keep in mind that the SQLite folks only recommend that you use it for low to medium traffic websites. MySQL is a better solution for high traffic sites.