I have a web server running Plesk. I've created a test subdomain in apache and placed a copy of the site there to use for testing. Since doing that, memory usage on the server has gone up quite a bit. The files are the same, the tasks are the same... but if I restart Apache, and tool around on the live site for a while, the usage sits around 0.5gb / 2.0gb total. Visiting one page on the test site puts the usage up to 1.0gb straight away, and the usage then hovers around the 1gb mark.
My first question is, does it sound reasonable that a second virtual host would consume that much extra memory? I don't know much about these things but I can imagine that a bunch of resources are cached and/or reserved once the second virtual host starts getting used, and that the amount of resources required by two copies of that application would be twice that required by one copy.
My second question is, if that's the case, is there any way to tell the system that this test server is really low priority, and that I'm perfectly happy to wait longer for requests to it to go through, for it to free memory after it's done stuff, etc?