Tuesday, August 02, 2005

Overcomming Recovery Storage Group Limitation

The Recovery Storage Group (RSG) works great for recovering deleted items to a production database. The limitation is that the mailbox has not been moved or deleted (purged) from the original database. The Recovery Storage Group process compares two attributes before allowing a restore of mailbox items from the restored database to the production database: The msExchMailboxGUID (read only) one the mailbox and msExchOrigMDB on the database in the RSG.

Dealing with a deleted mailbox:
A mailbox's GUID (msExchMailboxGUID) is the same for the life of the mailbox. Restoring a deleted (purged) mailbox by recreating it will not not allow the RSG to connect the new maibolx to the mailbox that exists in the restored database. The new recreated mailbox has a new GUID and it cannot be changed to match the old one (the msExchMailboxGUID is a read only attribute). Microsoft recommends the following steps:
1. Add the database the mailbox was in before it was purged to the RSG
2. Restore the databse to the Recovery Storage Group
3. Mount and then dismount the database in the RSG (this will ensure that the database is in a clean shutdown state eseutil /mh databasename.edb
4. Create a new Storage Group and Database ensuring that the file names for the new database are identicle to those of the database in the RSG. Then dismount the database.
5. Copy the .stm and .edb files from the RSG location to the path of the new database.
6. In the properties of the new database (through ESM) place a check mark next to the box (this database can be over written by a restore).
7. Mount the database, connect mailbox to an AD account, Exmerge the data out of the recovered mailbox and into the new mailbox.

Dealing with a mailbox that was moved:
A database in the RSG will have an attribute called msExchOrigMDB set to the distinguished name of the original database. If a mailbox has been moved to another database the only backup available may be of the database before the mailbox was moved. To restore items Microsoft recommends the following steps:
1. Move the mailbox back to the original database
2. Modify the msExchOrgiMDB attribute so that it lists the DN of the database that now holds the mailbox in question.

Related KB Articles: