What do the fields cs-bytes and sc-bytes mean in a log file?
You want to know what the fields xx-bytes mean in a log file

• cs-bytes: Number of bytes sent from client to appliance
• sc-bytes: Number of bytes sent from appliance to client

This can sometimes mean that bytes will be recorded even if the Origin content server (OCS) did not send anything down to the client. For example if we deny access to the website based on content the proxy still sends down a page to the client telling them they were denied access and hence we still record some bytes downloaded even though the user never saw the final site. These values will also represent the bytes served from Proxy's cache.