US Patent 7568078 Epoch-based MUD logging

Methods and apparatus for performing MUD logging for a volume in a system implementing network-based virtualization are disclosed. This is accomplished by enabling two or more MUD loggers to separately maintain a MUD log for the volume. Through enabling the MUD loggers to communicate, the MUD loggers may update their respective MUD logs. Each MUD log includes information for one or more epochs, where the information for each of the epochs indicates a set of one or more regions that have been modified during the corresponding epoch.