If you plan to keep using SMB for now, I recommend to at least move the db’s to the system running the node. You can find instructions here: How to move DB’s to SSD on Docker
The post is about moving to SSD, but could be used to move them to a local HDD too.
Using the db’s over SMB has caused a lot of problems for nodes. At the least the locking issue is just going to get worse the more data you get.
You’re right, it shouldn’t. This is not normal behavior. People are running nodes without problems on raspberry pi’s.
Since you mention a running parity check, it’s possible that a combination of the storj file walker process or garbage collection with that parity check led to high IO. The 95% CPU could have been just IO wait. In that case upgrading the CPU wouldn’t do anything. But even without that I’m certain a 6 core xeon silver is already overkill for a storage node. If you want a new CPU for other reasons then it can’t hurt, but buying a new one for Storj wouldn’t be worth it.