An adapter that splits a single PCIE slot(x16) to hold 4 x M.2 NVMe SSDs(x4 each) would be a great way to persist a Redis instance that is not just serving as a cache.
If the same can be done with Optane SSDs, the lower latency will at higher queue depth will certainly help.
If the same can be done with Optane SSDs, the lower latency will at higher queue depth will certainly help.