As you know, ARRv2 RC was released a few weeks ago. (To learn more about ARRv2, click here. Download x64 or x86.) With ARRv2 RC, ARR now has two cache tiers, kernel memory cache and disk cache. I think people in general understand the benefits of caching (reduced latency, reduction in bandwidth consumption, etc) but recently, a customer who has deployed ARRv2 RC in production sent me the following data. The customer is using ARR as a reverse proxy to load balance the requests to several content servers.
The data on the left is from the content servers (aggregated) and the data on the right is from ARR. In this customers environment, over the course of 4 days (duration of time in Oct when the logs have been captured), he saved approximately 100GB worth of bandwidth (160GB total bytes in ARR vs. 62GB at the content servers). Of course, your mileage may vary depending on the cache-ability of the contents that you serve, but savings of 100GB in 4 days is significant for this customer.
I was really impressed to see the "real customer" data on ARR cache performance so I figured I would share it on iis.net. If you haven't already, check out ARR and see what it can do for you in your environment. ARRv2 RC comes with GoLive license, which means it can be deployed in production.
Note: Because some of the contents are being served from the cache in ARR, if you are providing logs to your customers, you will need to gather logs from ARR as well as from the content servers to provide the complete log.