The Queue Length is the number of read or write operations waiting to be completed on an EBS volume. The optimal queue length for a volume depends on the volume type, your application’s workload, and your application’s latency and throughput needs.
Blue Matador detects anomalies on the average queue length on a volume so that they can be correlated with any other issues on a volume. For some workloads a high queue length can indicate an unexpected increase in traffic. For others, a low queue length may indicate that a database server has died.