Cache reheating refers to the process by which a database server must re-load its cache after a server restart. This can be a significant issue if not handled properly, as it can cause a temporary overload on the database server and slow down query performance. However, MongoDB's storage engine uses memory-mapped files, which eliminates the need for reheating after a process restart. When handling reheating scenarios, it is essential to consider operational strategies such as scheduling OS maintenance during off-peak hours, restarting the mongod process safely, remounting volumes to lose file system cache information, and copying only the newest datafiles to force sequential reheat and faster query performance.