1. A method executed by a storage system, comprising: generating input/output (IO) commands by plural applications executing on a host; retrieving, from a table stored in a host bus adapter (HBA) located in the host, classifiers that assign different priorities to different applications of the plural applications executing on the host; prioritizing the different applications at the HBA by inserting the classifiers into the IO commands at the HBA; and processing the IO commands at a storage device according to the priorities assigned by the classifiers for the different applications at the HBA.