ReplayEngine creates snapshots of a thread when it is record mode. It does not create these snapshots for each statement your program executes. Instead, it selects places it thinks are important. After a snapshot it saves incremental changes until the next snapshot.

ReplayEngine stores snapshots in /tmp. ReplayEngine keeps a limited number of these snapshots around and prunes older one as your program executes so that it can conserve space. If your system has a small /tmp area, ReplayEngine may fill it up. If this occurs, you must increase the amount of storage allocated to /tmp.

ReplayEngine changes your program's the amount of memory your program uses as it also keeps state information in memory.

While in replay mode. ReplayEngine creates extra processes, usually around ten, but you may see up to thirty. You should ignores these processes as they are only used by ReplayEngine. These processes appear in the output of the ps command.