I'm going to let it run, fully functional for as long as I can and I will report back how things go. Thank you for helping me get everything running as it should be.
Don't forget that the ISPConfig memory usage is different from the postfix usage, they are not the same
Should ISPconfig "perfect server" with everything installed be too much heavy lifting for a basic VPS server like mine-- Do you have a suggestion of a more lightweight solution (preferably with a guide) to setup an email server?
No I don't think so since ISPConfig is not using up the ram but postfix is doing that. What every other solution you're installing, you also have to install postfix which will cause the same problem. I'm not a postfix or ISPConfig/linux expert, just talking about my own experiences I encountered and the solutions I used. Maybe there is a very simple solution or fix for the problem you're having which I don't know of. The experience I had with other servers is that the ram was at about 100% and errors appeared in my mail.log stating that postfix/amavisd could'nt work because there was not enough memory. That was the reason for me to clear the cache every now and then
Got it. I wonder if the performance of my mail server was acting up because the emails were just spinning around in there, unable to escape out of the queue. It seems to be working fine right now, even with 92% memory usage, but I wonder what would happen if i shoot out an email newsletter to 100 people.
You will have to test out things like that. I'm curious what happens when you reach (almost) 100% usage
