What should be monitored to troubleshoot performance issues for an instance using provisioned IOPS?

Monitoring the VolumeQueueLength is crucial for troubleshooting performance issues in instances that use provisioned IOPS. The VolumeQueueLength indicates the number of input/output operations (IOPs) that are waiting to be processed by the volume. When this queue length is consistently high, it suggests that the volume is either being overwhelmed by the number of requests or that it is not capable of processing the requests quickly enough.

In environments that leverage provisioned IOPS, performance degradation can occur if the volume cannot meet the expected IOPS levels. The average queue length provides insight into how many operations are pending and helps in identifying bottlenecks. If the queue length is excessively high, it often indicates that the workload is exceeding the volume’s capacity to handle IOPS, and further investigation may be needed to understand whether the volume size is adequate, if the provisioned IOPS are set correctly, or whether the application layer can be optimized.

Monitoring this metric allows administrators to make informed decisions about adjusting configurations, scaling the instance, or implementing load balancing to optimize performance. The metrics related to read and write times, while important, do not directly reflect the immediate queuing issues that can cause slowdowns, making VolumeQueueLength a more effective focus point for troubleshooting in this context.