Ernie Souhrada, DBA chez Pinterest, explique comment il a drastiquement amélioré les perfs mysql sans changer de hardware.
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When we enable all of the optimizations, we find we can achieve roughly 500 percent more read and write throughput at both 16 and 32 threads while simultaneously reducing p99 latency by over 500ms in both directions. On the read side, we go from approximately 4100 – 4600 QPS to just over 22000 – 25000, depending on concurrency. On the write side, we go from approximately 1000 QPS to 5100 – 6000 QPS. These are massive gains in headroom and performance achieved with just a few simple changes.
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sur du i2.4xlarge (de la grosse instance ec2 de porc), percona-server-5.6, ubuntu 12.04.

Voir aussi http://www.slideshare.net/denshikarasu/all-your-iops-are-belong-to-us-a-pinteresting-case-study-in-mysql-performance-optimization
qui va plus dans les détails, avec les tests sysbench pour les différents disques, versions de kernel, modifs my.cnf, irqbalance, options de montage, etc... qui ont permi de tirer les conclusions.

On apprend notamment que le kernel en version 3.18 montre de meilleurs perfs IO qu'en 3.13.

Très pointu.