Please, let me know if there is a tool, which allows to give different reading (writing) priority to different users on Linux. I am looking for something similar to 'ionice' but able to set I/O priorities per file system and per user instead of per process. Using ionice assumes that each process accessing file system would have to be started in a special way or its priority would have to be adjusted once it is started - this is not a safe way to do it. For example, if some time critical production processes need to read/write some data to a file system, they need to have ultimate priority to do so, while lower priority processes (like backup or research) should have some low priority. It is not safe to assume that each user will always remember to use ionice whenever they read something from such shared file system. It would be much better to just give specific sets of users different priorities accessing a specific file system.
Thank you for your help!