clarify 4 GB total with swap

Author: coding-horror

docs/INSTALL.md

@@ -17,7 +17,7 @@ Alternately, you can try the [unofficial Heroku install guide][2], or the [BitNa
 ### Hardware
 
 - Dual core CPU recommended
-- 2 GB RAM recommended (1 GB can work, but you'll need swap ..)
+- 2 GB RAM recommended (and 2 GB of swap space)
 
 ### Software
 
@@ -39,7 +39,7 @@ Alternately, you can try the [unofficial Heroku install guide][2], or the [BitNa
 
 ### Low memory (less than 2 GB)
 
-Remember you *will* need swap enabled and working! To reduce memory footprint, clockwork can run inside your web server. If you launch the your web server with `EMBED_CLOCKWORK=1`, clockwork will run in a backgroud thread. As clockwork itself only performs scheduling, it will have very little impact on performance.
+Remember you *will* need swap enabled (enough for a total of 4 GB, so 2 GB swap with 2 GB RAM, and 3 GB swap with 1 GB ram, etc) and working! To reduce memory footprint, clockwork can run inside your web server. If you launch the your web server with `EMBED_CLOCKWORK=1`, clockwork will run in a backgroud thread. As clockwork itself only performs scheduling, it will have very little impact on performance.
 
 [1]: https://github.com/discourse/discourse/blob/master/docs/INSTALL-ubuntu.md
 [2]: https://github.com/discourse/discourse/blob/master/docs/HEROKU.md