The directory and information store services each independently maintain two reserve files ¾ Res1.log and Res2.log. These files are stored in the Mdbdata and Dsadata directories. Reserve log files are used when the directory or information store service renames its Edb.log file and attempts to create a new Edb.log file without enough disk space for the new Edb.log file. This is a fail-safe mechanism that is only used in the event of an emergency. When this situation occurs, an error message is sent to the respective service. The service flushes any transactions in memory that have not yet been written to a transaction log into the Res1.log file and, if necessary, the Res2.log file. When this process is complete, the service shuts down and records an event in the Windows NT Event Log. Note that like other transaction log files, RES (reserve) transaction log files are always 5 MB.