Hmm. Let’s say I add 6 SSDs, 2TB each, for a total of 600€. In a RAID6 configuration, that gives me 8TB of storage. Compare that to a classical NAS with 2×8 TB HDDs for a total of 350€.
The HDDs will draw around 4W idle each, 8W in total. Assuming 0.3€/kWh, over a span of 5 years, that is approximately 100€. The power consumption of the SSDs will be negligible.
So, just in terms of storage, the SSD solution is around 33% more expensive over 5 years. If you include the cost of the NAS itself, the price increment is even less noticeable.
Yes, absolutely. Right now, SSDs are probably superior in comparison to HDDs in every category except for price (and long-term data integrity when switched off). But when you consider large parity raids and take into account the cost of electricity, even the price difference might only be small, making SSDs even more attractive.