SteelHeadā„¢ Deployment Guide - Protocols : HTTP Optimization : Info-Level Logging
  
Info-Level Logging
You can look at the client-side SteelHead log messages to determine whether or not the HTTP optimization module is functioning. The logging level on the SteelHead must be set at info level logging for the messages to appear in the log. If the HTTP optimization module is prefetching objects, a message similar to the following appears in the logs. This only applies to the URL Learning and Parse-and-Prefetch. No log messages are displayed for Metadata Response or Object Prefetch Table.
Sep 25 12:28:57 CSH sport[29969]: [http/client.INFO] 2354 {10.32.74.144:1051 10.32.74.143:80} Starting 40 Prefetches for Key->abs_path="/" host="10.32.74.143" port="65535" cookie="rbt-http=2354"
The key specified in the log message is not necessarily the object that triggered the prefetch operation. In RiOS v6.0 or later, the log message includes the object that triggered the prefetch operation.