The checkpoint feature is used to log the execution process of a deduplication operation periodically. When a deduplication operation is stopped for any reason (such as system halt, panic, reboot, or last deduplication operation failed or stopped) and a checkpoint data exists, the same deduplication process can resume from the latest checkpoint file.
The checkpoint is created at the end of each stage or sub-stage of the deduplication process. In addition, for thesis start -s command, the checkpoint is created at every hour during the scanning phase.
If a checkpoint corresponds to the scanning stage (phase when the sis start -s command is run) and is older than 24 hours, the deduplication operation will not resume from the previous checkpoint automatically. In this case, the deduplication operation will start from the beginning. However, if you know that significant changes have not occurred in the volume during the past 24 hours, you can use the -p option with the sis start -s command to resume from the previous checkpoint without checking for the age of the checkpoint.