File folding describes the process of checking the data in the most recent Snapshot copy, and if this data is identical to the Snapshot copy currently being created, by referencing the previous Snapshot copy instead of taking up disk space writing the same data in the new Snapshot copy.
File folding saves disk space by sharing unchanged file blocks between the active version of the file and the version of the file in the latest Snapshot copy, if any.
The system must compare block contents when folding a file, so file folding might affect system performance.
If the folding process reaches a maximum limit on memory usage, it is suspended. When memory usage falls below the limit, the processes that were halted are restarted.