@stuartiannaylor: Just to answer a few of your talking points.
I was thinking of using a regular ATX power supply for several reasons, the main one is that it's cheaper to get 12V and 5V at pretty high amperage.
For instance I can find an brand new EVGA 600W with a single 12V49A rail and a 5V20A rail for less than 50€. More than enough to power safely the ROCKPro64 and 10 to 12 hard-drives.
Plus it's rated 80+, meaning less electricity wasted. And usually brand names power supply don't destroy all your hardware when they fail (which all power supply end up doing eventually, even brand names one as I have already experienced it after 7 years 24/7 powered on).
It has 6 SATA power connector, that can be doubled using adapters like these.
Power supply, for machines running 24/7, is really not something you can really spare expenses on.
I looked over for a USB3.0 solution, using a PCI-E like the one you linked. UASP adapter with 12V input for 3.5" harddrives are not that cheap either, I have found models like this one for instance. Plus I'd need a few USB3.0 hub to connect 2 to 3 UASP adapters per USB ports on the controller, with maybe 5V external connection to not overpower the PCI-E controller with that much disks.
In the end it won't be cheaper than the IOCrest SI-PEX40097 SATA controller, and it's a less clean solution, but it's a fallback solution for sure.
For the casing, I'd still go the individual hot-swap from the front route as it's way more practical IRL, even if it cost more. The Orico one can be found for 8.75€ a pop when bought by 10 or more.
Software wise, I'd need to do some more research into it, and some testing before going toward a different solution than what I already use. But on first glance Snapraid seem to have many advantages indeed.
EDIT: the USB solution could be cheaper using something like these:
https://m.fr.aliexpress.com/item/32897789991.html
https://m.fr.aliexpress.com/item/32829472708.html
I was thinking of using a regular ATX power supply for several reasons, the main one is that it's cheaper to get 12V and 5V at pretty high amperage.
For instance I can find an brand new EVGA 600W with a single 12V49A rail and a 5V20A rail for less than 50€. More than enough to power safely the ROCKPro64 and 10 to 12 hard-drives.
Plus it's rated 80+, meaning less electricity wasted. And usually brand names power supply don't destroy all your hardware when they fail (which all power supply end up doing eventually, even brand names one as I have already experienced it after 7 years 24/7 powered on).
It has 6 SATA power connector, that can be doubled using adapters like these.
Power supply, for machines running 24/7, is really not something you can really spare expenses on.
I looked over for a USB3.0 solution, using a PCI-E like the one you linked. UASP adapter with 12V input for 3.5" harddrives are not that cheap either, I have found models like this one for instance. Plus I'd need a few USB3.0 hub to connect 2 to 3 UASP adapters per USB ports on the controller, with maybe 5V external connection to not overpower the PCI-E controller with that much disks.
In the end it won't be cheaper than the IOCrest SI-PEX40097 SATA controller, and it's a less clean solution, but it's a fallback solution for sure.
For the casing, I'd still go the individual hot-swap from the front route as it's way more practical IRL, even if it cost more. The Orico one can be found for 8.75€ a pop when bought by 10 or more.
Software wise, I'd need to do some more research into it, and some testing before going toward a different solution than what I already use. But on first glance Snapraid seem to have many advantages indeed.
EDIT: the USB solution could be cheaper using something like these:
https://m.fr.aliexpress.com/item/32897789991.html
https://m.fr.aliexpress.com/item/32829472708.html