The present invention is directed toward the resumption of a journaling process in a data management appliance after a period of unavailability. The data management appliance is a random-access storage system that at the logical block level replicates the contents of a primary storage system over time. A small "dirty extent map" is established on the primary storage device. The dirty extent map keeps track of which portions of primary storage are written to while journaling is interrupted. When journaling is resumed, the contents of the dirty extents are compared to the latest replica of the primary storage to identify the differences. These differences are then journaled as if they were write commands. Meanwhile, new write commands are also journaled by the data management appliance. Once the differences of all of the dirty extents have been journaled, the data management appliance may resume normal journaling operation.