Curious if this is possible... if I have 2 identical cache drives as "cache" and "cache 2", is it possible to simply change their order without rebuilding/losing data?  I realized that the primary cache is the nvme drive in the slot right next to my video card so it takes more heat (even with a heatsink, 8C hotter than the nvme under the motherboard cover) and being primary, all the reads mostly take place there generating more workload/heat.  Wondering if possible or would provide any benefit to simply switch them so that nvme drive is cache 2.

If you have 2 identical drives set up as cache then I would expect them to get equal amounts of reads/writes.   What makes you think one gets more than the other?  Unraid does not have any concept of a ‘Primary’ drive in a cache pool.

 

Having said that, since Unraid recognises drives by their serial number and not by where they are connected you could always swap them over in the physical machine without making any changes at the UnRAID level.   I doubt it would help though.