My network guys have started asking me about a sudden spike in network traffic that they noticed. For the past 4 days I have had about 5 terabytes go between my 3 CD servers and my 1 CM server, which is significantly more than I've ever seen before. I'm on Sitecore 8.1 Original release (and have been on this release since April of this year). At the same time my SOLR disk space requirements have significantly increased, causing me to request extra disk space 2 times in that same time frame. My SOLR Server is on the same machine as my CM server, and my analytics SOLR index has grown very large as well.
I'm not sure where to start looking to troubleshoot this kind of issue. There haven't been exceptions to be logged, there is just a lot more traffic than I was expecting. Our website traffic has not went up significantly in the last week, so I don't think that this is "normal" traffic.
How do I start troubleshooting this issue?