EC2 Instance

Troubleshooting performance issues with AWS EC2 instances.

James Lane
May 22, 2023

Importance of optimising EC2 instance performance

When it comes to AWS, EC2 instances are the backbone of cloud computing. Ensuring optimal performance is essential to deliver a seamless user experience, support high-traffic applications, and maintain the overall efficiency of your infrastructure. By optimising EC2 instances, you can minimise latency, reduce downtime, and improve the overall performance of your applications and services.

Troubleshooting EC2 Instance Performance Issues

To effectively troubleshoot performance issues with EC2 instances, follow these step-by-step guidelines:

Step 1: Monitoring and Benchmarking

Monitoring the performance of your EC2 instances is crucial to identify bottlenecks and areas for improvement. AWS offers various monitoring tools like Amazon CloudWatch, which provides insights into CPU utilisation, memory usage, disk I/O, and network activity.

Implementing App Performance Monitoring (APM) Agent

Implement a App Performance Monitoring (APM) agent such as NewRelic. It helps you to find which queries are causing the issue. The developers could have written a query with absolutely no brain, fix that.

Benchmarking techniques

Benchmarking allows you to compare your EC2 instance's performance against industry standards or your own performance goals. Conduct regular benchmarking tests using tools like Apache Bench or Siege to measure response times, throughput, and concurrency.

Step 2: Identifying Resource Bottlenecks

Check the CPU and memory utilisation of your EC2 instance. High CPU utilisation usually happens due to the app service, which opens/closes multiple file descriptors unnecessarily. High memory utilisation usually occurs due to unwanted looping or wrong variable handling in the app service. Fix these issues immediately. To identify the underlying causes of slow performance, focus on the following key resources:

CPU utilisation

Monitor CPU utilisation to ensure your EC2 instance has sufficient processing power to handle your application's workload. High CPU utilisation may indicate the need for a larger instance type or optimising your code for better efficiency.

Memory utilisation

Inadequate memory can severely impact performance. Monitor memory usage and consider increasing the instance's memory or optimising your application's memory footprint.

Disk I/O

Disk I/O bottlenecks can cause slow response times. Analyse disk I/O metrics, such as read/write throughput and latency, and optimise storage configurations accordingly.

Network bandwidth

Network congestion can degrade performance. Monitor network bandwidth usage and identify potential bottlenecks. Consider adjusting network settings or upgrading to higher bandwidth options.

Step 3: Optimising Resource Allocation

Efficient resource allocation is vital for optimal performance. Consider the following techniques:

Right-sizing EC2 instances

Evaluate your application's resource requirements and choose the appropriate EC2 instance type based on CPU, memory, and I/O needs. Avoid over provisioning or under provisioning resources, as both can impact performance.

Utilising Auto Scaling

Implement Auto Scaling to dynamically adjust the number of EC2 instances based on demand. This ensures your application can handle sudden spikes in traffic and avoids resource saturation.

Step 4: Improving Network Performance

Use MTR to check for ICMP or TCP packet loss and latency problems. Review hops on trace route or MTR reports using a bottom-up approach. For example, check for loss on the last hop or destination, and then review the following hops. If the packet loss or latency issues continue through the last hop, there might be a network or routing issue. Packet loss or latency on one hop in the path might occur if there's an issue with the control plane rate limiting on that node. Check if the last hop reported is the destination noted in the command. If it isn't, then there might be an issue caused by a restrictive security group.

Tuning TCP settings

Fine-tuning TCP settings can improve network performance. Adjust parameters like TCP window size, congestion control algorithms, and timeouts to achieve better throughput and reduced latency.

Utilising Elastic Load Balancer

Leverage Elastic Load Balancer to distribute incoming traffic across multiple EC2 instances. This not only improves availability and fault tolerance but also optimises network performance by avoiding single points of congestion.

Step 5: Implementing Performance Enhancements

To further enhance EC2 instance performance, consider the following strategies:

Caching strategies

Implement caching mechanisms, such as Amazon ElastiCache or Redis, to reduce the load on your EC2 instances. Caching frequently accessed data can significantly improve response times and reduce the load on your backend infrastructure.

Content delivery networks (CDNs)

Utilise CDNs like CloudFront to cache static content closer to the end-users, reducing latency and improving overall performance. CDNs help deliver content quickly by leveraging edge locations worldwide.


Optimising EC2 instance performance is vital for maximising the efficiency and reliability of your AWS infrastructure. By following the troubleshooting steps outlined in this article, you can effectively identify and resolve performance issues, resulting in improved user experiences and better application performance.