I am running a chat site and I'm expected to get a huge traffic surge within the following weeks. Millions of chat records, thousands of rooms and members. I am running an 8GB ram server with 1TB SSD and xeon E3 1230 v3. I am using the software nginx (default limits), mysql 5.5 (default limits) and php 5.5.20 (default limits) and ubuntu 14 (default limits). I am worried that the default limits are not enough for the expected surge. Can someone please direct me as to which limits should be raised appropriately for high traffic?