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Faster and bigger SSDs enable us to talk about something else than IOps

Bus overload on an old storage array after adding a few SSDs

The first SSDs in our storage arrays were advertised with 2500-3500 IOps per drive. Much quicker than spinning drives, looking at the recommended 140 IOps for a 10k SAS drive. But it was in fact still easy to overload a set of SSDs and reach its max throughput, especially when they were used in a (undersized) caching tier.

A year or so later, when you started adding more flash to a system, the collective “Oomph!” of the Flash drives would overload other components in the storage system. Systems were designed based on spinning media so with the suddenly faster media, busses and CPUs were hammered and couldn’t keep up.

Queue all sorts of creative ways to avoid this bottleneck: faster CPUs, upgrades from FC to multi-lane SAS. Or bigger architectural changes, such as offloading to IO caching cards in the servers themselves (e.g. Fusion-io cards), scale-out systems, etc.

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