Im on a linode vps with far less memory then the 4gb minimum wanted by mailcow. It has 1gb of memory. To account for this i have configured 2.5gb of swap with swapiness of 60. When mailcow is not running memory usage sits at 162mb and the swap is almost empty. when mailcow is running then the memory is almost full at 700mb and the swap starts to fill up too. it seems the primary consume is a bunch of mysqld processes. and yes, i have disabled clamav and solr. this is all according to htop. 
I understand i am well below the minimum specs and my large swap is a poor mans solution, but i still wish to optimize this further. my uses are not large scale. i just have a single user, and a single mailbox. this is only for a single support email on a website. I want to know if i can optimize and minimize this further because gigabytes of memory usage for a literal empty unused email server is ridiculous. Besides mailcow the main site is a python webserver using nginx as its reverse proxy.