Patent ID: 8639466

Claim:
A system comprising: at least one replaceable unit; at least one adaptor executing a program to perform operations, the operations comprising: identifying a replaceable unit in the system for replacement; switching the system into a service mode; switching the system into a test mode in response to the replacement of the replaceable unit with a replacement unit; determining at least one connected unit connected downstream to the replaceable unit from information associating the replaceable unit with at least one connected unit, wherein the information indicates downstream relationships among the at least one connected units and the replaceable unit; testing the replacement unit in combination with the determined at least one connected unit downstream from the replaceable unit forming an Input/Output (I/O) path for testing I/O in accordance with a predetermined testing policy so as to verify the functioning of the replacement unit by sending test data to the replacement unit and the determined at least one connected unit; and returning the system to an online mode if the testing of the selected elements is successful.