Ooof you have me worried. My R720XD shipped out yesterday and is supposed to arrive Monday. My plan was to install TruNAS Scale on it to replace my old tower with unraid installed on it. I have roughly 25 docker containers that I run. What kind of errors did you see? It’s scheduled to be installed in the data center week after next so I don’t have a bunch of time to troubleshoot.
6 nines is really really difficult. It’s hard to estimate costs without specific requirements, but a marketplace site with 1000 daily users means you’re expecting about 1 user per minute, which isn’t a lot. I’d imagine you could get by with the cheapest cloud hosting.
The real problem is that most major cloud providers don’t offer 6 nines. Even AWS only offers credits below 99.5%, so you’d want to not lock yourself into a single provider. My best suggestion is to have a small/cheap server with all of the big names and load balance/round robin between them.
I just finished building mine from KB-3D. Can’t recommend them enough. Their customer service is almost always around on the Voron discord and answered every stupid question I had along the way.
Power wise you are absolutely correct. It is not the best performance value anymore. However, support for the Pi4 is much more robust when using them in specific projects designed to use them.
I bought the rear backplane for the dual 2.5 inch drives in the back. Going to throw the boot OS on it so I don’t have to worry about a USB drive dying or becoming corrupted. Good luck on your journey. Really interested to hear how it goes.