Windows application performance deteriorates in EC2 instance created by custom AMI

Question

I have created a Windows custom AMI with some custom Windows application.I use this AMI to generate EC2 instances.

I have run into a strange issue:

• All the applications run smoothly in the EC2 instance created from the custom AMI.
• However, after 24 hours, when I created an EC2 instance using the same custom image, the performance of the applications deteriorate.
• Even opening an application on the EC2 instance is much slower compared to the EC2 instance which was created 24 hours prior.

Any Suggestions would be really helpful.

Answer 1

I got the issue. Apparently any windows app we launch , Microsoft automatically tries to connect to internet for updates for every 24 hours . In my case , Internet was turned off , The updates where not getting downloaded. hence the connection was in wait state of 15 seconds by default, Hence the application was slow to launch

Answer 2

This might be caused by the use of a T2 instance. These are burstable instances.

From CPU Credits and Baseline Performance for Burstable Performance Instances - Amazon Elastic Compute Cloud:

Traditional Amazon EC2 instance types provide fixed performance, while burstable performance instances provide a baseline level of CPU performance with the ability to burst above that baseline level. The baseline performance and ability to burst are governed by CPU credits. A CPU credit provides the performance of a full CPU core for one minute.

So, if your Amazon EC2 instance is consuming a lot of CPU, then it might run out of the CPU credit balance, and therefore be limited in the amount of CPU it can use.

You can monitor the CPU credit balance in Amazon CloudWatch. You can also see the historical CPU usage in CloudWatch, or do it within the Windows instance itself using the Task Manager.