"Our optimization framework is flexible and can be used to design a range of storage hierarchies. When applied to current workloads and prices we find the following in a nutshell: for many enterprise workloads capacity dominates provisioning costs and the current per-gigabyte price of SSDs is between a factor of 3 and 3000 times higher than needed to be cost-effective for full replacement. We find that SSDs can provide some benefit as an intermediate tier for caching and write-ahead logging in a hybrid disk-SSD configuration. Surprisingly, the power savings achieved by SSDs are comparable to power savings from using low-power SATA disks."
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