I use 1TB SanDisk (Raspberry 2) and 4GB Panasonic SLC (Raspberry 4) in my distributed database cluster: http://github.com/tinspin/rupy http://github.com/tinspin

I use 1TB SanDisk (Raspberry 2) and 4GB Panasonic SLC (Raspberry 4) in my distributed database cluster: http://github.com/tinspin/rupy http://github.com/tinspin/rupy In my experience industrial versions of mainstream cards are less reliable! I agree, you have to measure latency and longevity on these edge (maximum longevity or space) SD cards as bandwidth is limited by SPI (4 is not really that much faster than 2). USB3 is not stable enough for 99.9999 uptime. If you use the cards above and mostly write once on the 1TB and replicate all that data on 3 cards in 2 geographical locations in realtime (6x in total minimum = you have redundancy even if one node fails on local and global level) you should be fine. After having 8GB Odroid MMC fail on me twice after 5 years, I invested in Intel Atom servers with X25-E (65nm SLC 100.000 writes per bit) drives as backup plan if the SD card solution fails/has problems. Power goes from 2W to 25W (50W with 10x SATA SSDs) with that change so you cannot afford more than 1-2 Atoms per location as lead-acid backup will be too expensive/large otherwise. Remember, if you do not power flash memory for a long time the data is corrupted/lost. You need your disks to be powerable on solar/wind, in practice this means Raspberry 2 when the mains go. As electricity prices rise the supply quality will degrade. Power outages will increase exponentially until the powergrid fails without replacement parts/transport. Peak energy is not a speculation, it's the only sure thing.