@article {19484, title = {A Fault Model for Upgrades in Distributed Systems (CMU-PDL-08-115)}, journal = {Parallel Data Laboratory}, year = {2008}, month = {2008/12/01/}, url = {http://repository.cmu.edu/pdl/10}, author = {Tudor Dumitras and Kavulya, Soila and Narasimhan, Priya} }