Workloads that require low latency, fast random access, don't involve too much (re)writes, mobile environment, money is not an object: SSDs. Workloads that inv

Workloads that require low latency, fast random access, don't involve too much (re)writes, mobile environment, money is not an object: SSDs. Workloads that involve lots of writes and especially rewrites, transient and ephemeral data, don't require low latency or fast random access, money is a factor: HDDs. The key thing is that HDDs have a theoretically infinite amount of writes compared to SSDs which have a finite amount. Certain workloads are consequently going to be more suited for HDDs.