I am thinking of running multiple database/messages servers such as postgres, redis, mongo, influxdb on old computers and use a centralized NAS to store the data.
One advantage is that I don’t need to worry about getting appropriate local storage for the computers that host these services. For example, I could run postgres on an old desktop with spinning disks or even a raspberry pi.
But I am still concerned about the I/O speed and reliability. I wonder if anyone has experience doing it like this. Can you share the pros and cons? I really appreciate it.
not sure I understand, what OS should these computers run? should this also be NAS storage? Or is it just the database filesystem that should be on the NAS?
honestly it looks like you don’t have the knowhow to setup shared storage, it seems you are more a developer type of person, so KISS (Keep It Simple Stupid)
run local storage, your databases won’t be even gigabytes in size, get some cheap SSD drives instead (SATA) if you want I/O.
also all your databased won’t dive when your accidentally pull the power plug to your NAS or trip over the ethernet cable.