As Ceph is software-defined for storage, its performance is heavily affected by the speed of the CPUs in the OSD nodes. Faster CPUs mean that the Ceph code can run faster and will spend less time processing each I/O request. The result is a lower latency per I/O, which, if the underlying storage can cope, will reduce the CPU as a bottleneck and give a higher overall performance. Chapter 1, Planning for Ceph, stated a preference for high Ghz processors rather than high core count, for performance reasons; however, there are additional concerns with high-core-count CPUs when they are over-specified for the job.
To understand these concerns, we will need to cover a brief history on CPU design. During the early 2000s, CPUs were all single-core ...
