Abstract: An external request to perform a file operation within a resource manager is received. The resource manager selects a resource manager file identifier that is to be an attribute of a file associated with the file operation. The file operation and the resource manager file identifier are logged in a log entry of a log. Subsequent to logging the log entry, the log entry is accessed during a forward pass through the log, for example, during a roll-forward recovery. If it is determined that the resource manager file identifier in the log entry is assigned to the file, the first log entry is not processed. On the other hand, if it is determined that the resource manager file identifier in the log entry is not assigned to the file, the resource manager file identifier is selected to be assigned to a file when the first log entry is processed.

Abstract: The location of appropriate undo data necessary for reversing an effect of an operation performed at a computer system is identified during a forward pass through a log. A cycle count can be used to determine if appropriate undo data is stored in an object or is stored in auxiliary storage. If appropriate undo data is stored in an object and the undo data would be potentially lost by processing a redo log entry to modify the contents of the object, the appropriate undo data is copied to auxiliary storage. In some embodiments, a secondary computer system receives log entries from a primary computer system. The secondary computer system can identify undo data necessary to reverse an effect of an operation performed at the secondary computer system from received log entries. Identified undo data can be copied auxiliary storage at the secondary computer system.