here's how the story goes.

We started transforming a monolith, single-machine, e-commerce application (Apache/PHP) to cloud infrastructure. Obviously, the application and the database (MySQL) were on the same machine.

We decided to move to AWS. And as the first step of transformation, we decided to split the database and application. Hosting application on a c4.xlarge machine. And hosting database to RDS Aurora MySQL on a db.r5.large machine, with default options.

This setup performed well. Especially the database performance went up high.

Unfortunately, when the traffic spiked up, we started experiencing long response times. Looked like RDS, although being really fast for executing queries, wasn't returning results fast enough over the network to the EC2 machine.

So that was our conclusion after an in-depth analysis of the setup including Apache/MySQL/PHP tuning parameters. The delayed response time was definitely due to the network latency between EC2 and RDS/Aurora machine, both machines being in the same region.

Before adding additional resources (ex: ElastiCache etc) we'd first like to look into any default configuration we can play around with to solve this problem.

What do you think we missed there?

CodePudding user response：

One of the bigest strength with the cloud is the scalability and you should always design your application to utilise it and it sounds like your RDS instance is getting chocked due to nr of request more than the process time for the queries. So rather go more small instances with load balancing than one big doing all the job. And with Load Balancers you will get away from a singel point of failure due to you can have replicas of your database and they can even be placed in different AZ.

Here is a blogpost you can read on the topic: https://aws.amazon.com/blogs/database/scaling-your-amazon-rds-instance-vertically-and-horizontally/

Good luck in your aws journey.

CodePudding user response：

The Best answer to your question is using read replicas, but remember only your read requests could be sent to your read replicas so you would need to design your application that way

Also for some cost savings, you should try aurora serverless

One more option is passing traffic between ec2 and rds through a private network rather than using the public internet to connect your ec2 to rds that can be one of the mistakes that might be happening