Why it is Incorrect to use Average Block Size for Storage Performance Benchmarking

Just a quick post to address something many people either get wrong or just live with due to convenience.

In summary: Please, let’s stop using average I/O sizes to characterize storage system performance. It’s wrong and doesn’t describe how the real world works. Using an average number is as bad as using small block 100% read numbers shown in vanity benchmarks. Neither is representative of real life.

Using a single I/O size for benchmarking became a practice for a vanity benchmark and to provide a level playing field to compare multiple products.

But, ultimately, even though the goal of comparing different systems is desirable, using a single I/O size is fundamentally flawed.

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