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by marginalia_nu 1496 days ago
Besides what you've mentioned, overprovisioning/garbage collection may also cause slowdowns after sustained writes.

The more I've worked with SSDs to try to get them to perform well, the more I've come to realize benchmarking SSD performance is virtually impossible to do in any meaningful sense, because they themselves are stateful and your performance is highly dependent not only on what you are doing now, but what you did a few moments ago. There's also a bunch of protocol-level behavior adding to this, as well as os-level behavior that may be difficult to isolate, and even if you succeed, yeah, you're benchmarking the device in an unrealistic fashion unlike any actual real world usecases so congrats I guess.

1 comments

Typically there are a few primary modes of the state. It’s useful to understand the performance under each mode. Even if you want predict exactly what mixture of modes you’ll be in, you can have a good guess if you’ll be in some pathological behavior based on your workload.