Today, Amazon announced the availability of a new CloudWatch metric called EBS Stalled I/O Check to monitor the health of your AWS EBS volumes. You can use this CloudWatch metric to monitor the status of the I/O being driven on your EBS volume to determine when your volumes are impaired. With this new volume level metric, you can now quickly detect and respond to EBS impairments that may potentially be impacting the performance of your applications. The metric will return a 0 (pass) or a 1 (fail) status based on if the EBS volume is processing requested I/O operations. With Amazon CloudWatch, you can use the new metric to create customized dashboards and set alarms that notify you or automatically perform actions based on the metric.
Source:: Amazon AWS