I work for a small company that is going to upgrade our infrastructure to an S2D cluster. We figured we might as well get some NVMe drives for cache for the extra performance, however there doesn't seem to be any small capacity enterprise-grade NVMe drives with PLP. All the modern generation NVMe drives release this year and last year are all 1+ TB and above. We need a minimum of 2 per server for cache, plus a spare, so for seven NVMe drives we're looking at ~$8,000.
I was wondering if using more SATA SSDs for cache would yield a performance increase in a similar manner in which more columns on capacity drives yields more performance. For example, 4 SATA SSD Cache + 8 Capacity HDDs, instead of 2 SATA SSD Cache + 8 Capacity HDDs? The S2D documentation doesn't seem entirely clear on exactly how the cache functions and if more cache drives yields more performance. Do cache drives have columns too, just like the capacity drives, yielding more performance with more drives?
Obviously storage metrics are more complex than just N number of SATA SSDs = NVMe SSD, but if more cache drives can improve performance then maybe it's a more cost effective alternate when NVMe are just a nice to have and not a must have.