Recovery Database in Exchange 2010

All of you know that there are no storage groups in Exchange 2010 and hence no recovery storage groups as well. A recovery database (RDB) serves the functions carried out by a recovery storage group in previous versions of exchange. Few points need to be understood before we start playing with restore options in 2010.

• You cannot create a recovery database using the console. Use shell instead (New-MailboxDatabase -Recovery -Name RDB -Server “servername” -EdbFilePath "path" -LogFolderPath "path” )
• Recovery database can only be used for 2010 databases. Previous versions are not supported.
• You cannot create mailbox database copies of a recovery database.
• Online maintenance isn't performed on a recovery database.
• You cannot enable circular logging on RDB.
• A recovery database cannot be used to recover public folder data.
• Only one RDB can be mounted on a mailbox server at any time.
• Access to RDB using Outlook or OWA is not allowed.
• Mailbox management policies are not applied on a RDB.
• Mailboxes in a recovery database cannot be connected to user accounts.
• Data from a RDB can be merged to an existing mailbox or exported to a folder.

http://www.howexchangeworks.com/2010/01/recovery-database-in-exchange-2010.html