Causes for sudden high amount of disk read activity

Question

What could be the causes of a sudden one-time high amount of disk read activity? This has followed with an AWS notification of instance reboot schedule. Could it be that the physical server hosting the instance was compromised? Can the AWS team assure that it is maintaining good security of the infrastructure beyond a customer's control? There does not appear to be an easy way to directly reach or communicate with AWS official team to understand the issue thoroughly so it can be avoided again in future.
Thanks for your attention.

Answer

The sudden increase in disk read activity on an AWS instance can be attributed to factors like:

* The first write operation on some instance store volumes is slower than subsequent writes, impacting initial performance but generally balancing out over time.
* The efficiency of I/O operations varies based on the volume type (SSD or HDD). Amazon EBS optimizes performance by merging smaller, sequential I/O operations or splitting larger ones.
* Tools like CloudWatch provide metrics (e.g., VolumeReadBytes, VolumeWriteBytes, VolumeReadOps) that help in understanding and diagnosing performance characteristics of EBS volumes.

These factors, along with your instance configuration and workload, could explain the observed disk read activity spike. Monitoring and adjusting your configuration based on these insights can optimize performance. For more targeted assistance, AWS support might provide further insights, especially under a support plan that allows direct communication.

For ref:
* https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/disk-performance.html
* https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ebs-io-characteristics.html

Causes for sudden high amount of disk read activity

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