To tune your environment, you need to be able to collect information about your network. You need to know how to gather and analyze tuning statistics, determine the amount of coattailing (when more than one piece of data is being transferred in or out of the host with a single I/O operation) taking place in your network, analyze slowdown conditions, and monitor your common storage areas.

VTAM® provides operator commands and other facilities to help you gather this information. See Tuning tools for a description of the tools that you can use to gather data to tune your network.