price isn't the only thing to consider. speed and density matter too. if I have 1pb of storage across 10 servers on hdds, the networking cost will be much highe

price isn't the only thing to consider. speed and density matter too. if I have 1pb of storage across 10 servers on hdds, the networking cost will be much higher than 1pb across 2 servers on ssds, and will the retrieval times. when speed and density are considering factors, ssds make sense. when I needed 1.2pb of data fully searchable with retrieval times under 3s (across the entire data set, or huge portions.like half or quarter of the data), hdd wasn't even on the table. but we did use hdd for off-site backups of the data in case we hit a huge shtf scenario.