> When attached to an EBS–optimized instance, General Purpose SSD (gp2 and gp3) volumes are designed to deliver at least 90 percent of their provisioned IOPS performance 99 percent of the time in a given year. This means a volume is expected to experience under 90% of its provisioned performance 1% of the time. That’s 14 minutes of every day or 86 hours out of the year of potential impact. This rate of degradation far exceeds that of a single disk drive or SSD.
> This is not a secret, it's from the documentation. AWS doesn’t describe how failure is distributed for gp3 volumes, but in our experience it tends to last 1-10 minutes at a time. This is likely the time needed for a failover in a network or compute component. Let's assume the following: Each degradation event is random, meaning the level of reduced performance is somewhere between 1% and 89% of provisioned, and your application is designed to withstand losing 50% of its expected throughput before erroring. If each individual failure event lasts 10 minutes, every volume would experience about 43 events per month, with at least 21 of them causing downtime!<p>These are some seriously heavy-handed assumptions being made, completely disregarding the data they collect. First, the author assumes that these failure events are distributed randomly and expected to happen on a daily basis, ignoring Amazon's failure rate statement throughout a year ("99% of the time annually"). Second, they argue that in practice, they see failures lasting between 1 and 10 minutes. However, they assert that we should assume each failure will last 10 minutes, completely ignoring the severity range they introduced.<p>Imagine your favorite pizza company claiming to deliver on time "99% of the time throughout a year." The author's logic is like saying, "The delivery driver knocks precisely 14 minutes late every day -- and each delay is 10 minutes exactly, no exceptions!". It completely ignores reality: sometimes your pizza is delivered a minute late, sometimes 10 minutes late, sometimes exactly on time for four months.<p>As a company with useful real-world data, I expect them not to make arguments based on exaggerations but rather show cold, hard data to back up their claims. For transparency, my organization has seen 51 degraded EBS volume events in the past 3 years across ~10,000 EBS volumes. Of those events, 41 had a duration of less than one minute, nine had a duration of two minutes, and one had a duration of three minutes.