Storage Performance Troubleshooting Across Block and Object
Explore how to classify and troubleshoot storage performance issues in AWS block storage (EBS) and object storage (S3). Understand distinguishing symptoms such as throughput or latency limitations, analyze system metrics, and apply safe configuration adjustments to improve reliability and reduce service latency.
Slow storage can mean several different things, and each one points to a different fix. Before troubleshooting can begin, the kind of slow being looked at needs to be identified.
The first distinction is what kind of storage is involved. EBS is block storage: a volume attached to a single EC2 instance, where the application reads and writes data as if it were a local disk. S3 is object storage: a service called over the network to store and retrieve whole objects, shared across any number of clients. They fail differently, so the evidence checked for each one is different too.
The second distinction is what kind of slow is being seen. A throughput-limited system can move data, but not as much of it as is being asked for. Requests queue up, and the metric to watch is volume or bandwidth, not per-request timing. A latency-limited system moves plenty of data, but each individual request or operation takes longer than expected. And sometimes storage isn't the problem at all. The slowness is coming from somewhere else in the request path, and storage metrics will show nothing unusual.
Classifying a symptom into one of these three buckets, throughput-limited, latency-limited, or not-storage, is the first move in every storage incident. Getting that classification right reveals which metrics matter and which remediation is even worth trying. Getting it wrong leads to time spent tuning a volume that was never the bottleneck. ...