The following is tip #14 from "20 tips on protecting and recovering Exchange data in 20 minutes," excerpted from the book, "Mission Critical Microsoft Exchange 2003" (Digital Press, a division of Elsevier, Copyright 2004). For more information about this book and other computing titles, please
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Once all log and patch files have been recovered from the backup set, the backup application makes a call that was first introduced in Exchange 2000. If you recall previous versions of Exchange, the Restore_In_Progress key is created in the system registry during a recovery operation. This key contains information about the recovery operation in progress for the data-base engine (of which there is only one instance in Exchange 5.5 and previous versions). In Exchange 2000/2003, however, there are multiple instances of the database engine (storage groups), as well as concurrent recovery capabilities, and a single key in the registry will not suffice. This led to the advent of the RESTORE.ENV file (which stands for "Restore Environment"). Because a single registry key won't do in the case of concurrent recovery, the RESTORE.ENV file is created during recovery by the backup application when it calls HrESERestoreSaveEnvironment. ESE returns the necessary information (similar to that which was stored in the Restore_In_Progress key in previous versions of Exchange) to the backup application, and the RESTORE.ENV file is saved in the temporary location with the log and patch files. You can view the contents of the RESTORE.ENV file using the ESEUTIL program with the /CM switch. The log, patch, and RESTORE.ENV files will be used to complete the recovery operation in the next step.
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About the author: Jerry Cochran is a contributing editor for Windows IT Pro and Exchange & Outlook Administrator and a group program manager for Microsoft. He is the author of Mission-Critical Microsoft Exchange 2000 (Digital Press).