Sudden down of ec2 instance - t3.medium

Based on the information provided, it appears you're experiencing intermittent performance issues with your t3.medium EC2 instance used for hosting your course and lab environment. This behavior is likely related to the nature of T3 instances and their CPU credit system.

T3 instances, including t3.medium, are burstable performance instances. They provide a baseline level of CPU performance with the ability to burst above that baseline when needed. These instances accumulate CPU credits when operating below the baseline threshold, which can then be used to burst performance when demand increases.

The sudden slowdowns you're experiencing could be due to the depletion of CPU credits. When your workload consistently requires more CPU resources than the baseline provides, you may exhaust your accumulated credits. Once the credits are depleted, the instance's performance drops to the baseline level, which can result in perceived slowdowns.

The temporary improvement after rebooting the instance might be due to a brief period where the workload is less intensive, allowing some CPU credits to accumulate. However, if the workload continues to be CPU-intensive, you'll likely experience slowdowns again as credits are consumed.

To address this issue, consider the following options:

1. Monitor your CPU credit balance and usage to understand if credit exhaustion is indeed the cause of the slowdowns.

2. If you consistently need more CPU power than the baseline provides, consider switching to "Unlimited" mode for your T3 instance. This allows the instance to burst beyond the baseline indefinitely, but may incur additional charges.

3. Evaluate if a different instance type might be more suitable for your workload. If you consistently need high CPU performance, a compute-optimized instance (C-type) or a general-purpose instance with consistent performance (M-type) might be more appropriate.

4. Optimize your application to reduce CPU usage where possible. This could involve caching frequently accessed data, optimizing database queries, or distributing the workload across multiple instances.

5. If the issue persists, examine your system logs and application logs for any errors or unusual activity during the slowdown periods.

Remember to regularly monitor your instance's performance metrics, including CPU utilization, memory usage, and network activity, to better understand and address any performance issues.

Sources
Cloud Compute Instances – Amazon EC2 Instance Types – AWS
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