I've been reading some EBS docs
and they are talking about "I/O credit balance" How can I view my current (or historical) credit balance?
Each volume receives an initial I/O credit balance of 5,400,000 I/O credits, which is enough to sustain the maximum burst performance of 3,000 IOPS for 30 minutes. This initial credit balance is designed to provide a fast initial boot cycle for boot volumes and to provide a good bootstrapping experience for other applications. Volumes earn I/O credits every second at a base performance rate of 3 IOPS per GiB of volume size. For example, a 100 GiB General Purpose (SSD) volume has a base performance of 300 IOPS.