In order to improve the performance and efficient usage of our MARS system the server produces a warning whenever some inefficient access pattern is detected. A typical inefficient request pattern usually involves repeated access to elements of data which are stored in a single tape using individual requests. This pattern forces multiple mounts of a tape (which is a very expensive action for a tape-based mass storage system) which could be avoided if a single combined larger request were to be used.
We could recommend you to read Guidelines to write efficient MARS requests, but please do contact our ServiceDesk via email or our support portal if you need any further advice.