Recovery Storage Group (RSG) is a feature that was first introduced in Exchange 2003 edition. Owing to its popularity and usage to recover mailbox databases, this feature was carried forward in Exchange 2007. Basically, is a unique kind of storage group that gives an administrator opportunity to mount and extract database. Further, the extracted data can be merged to existing Server. Earlier in Exchange 2003, the job of extracting RSG database was performed by ExMerge tool and in Exchange 2007 it is done by Restore-Mailbox cmdlet or ExDRA tool.
Why Recovery Storage Group (RSG) is Different?
Reason #1) Standard protocols for sending and receiving messages are disabled (POP3, IMAP4, and SMTP) and only MAPI is enabled. This means sending and receiving of emails is restricted.
Reason #2) In spite of MAPI protocol supported, the mailbox database will not be reflected in Outlook or Outlook Web Access. Mailboxes mounted to RSG would not be connected to Active Directory accounts.
Reason #3) The management policy for user mailbox and RSG mailbox is completely different. Online maintenance tasks like defragmentation is not possible with RSG.
Reason #4) Unlike a user-mailbox, RSG cannot be set for automatic mounting once Information Store gets started. A maximum of 50 storage group for one Server can be mounted on RSG for recovery.
When to Use Recovery Storage Group?
Any strategy adopted for recovery has cons and pros, so does Recovery Storage Group (RSG). Here are some of the scenarios that will define when to utilize this recovery technique for recovering Exchange® mailboxes:
When?
Dial Tone Recovery: A dial-tone database is set up and original database has to be recovered using RSG. Dial-tone DB can be on same or different Server.
Deleted Mailbox Recovery: If any user-mailbox is permanently deleted, then backup can be restored to RSG for recovery. This will not hamper original database.
Specific Item Recovery: If a particular piece of information is lost and has to be searched (especially in case of eDiscovery) from backup, RSG can be used.
When Not?
For Public Folder Recovery: RSG only supports recovery of user mailboxes. Hence it should not be considered as an option for PF recovery.
For Restoring Entire Server: The idea of using RSG works efficiently for recovery of single storage group at a time. Entire Server databases cannot be restored.
For Rebuilding AD: For urgent time where there is need to rebuild/change Active Directory, utilizing RSG is not a good idea.
How to Create Recovery Storage Group Exchange 2007
Step1) Open Exchange Management Shell and navigate to “Toolbox” node in the console tree. In the result pane, click on “Database Recovery Management”
Step2)– Fill up the text box for “Server name” and “Domain Controller name” fields. Click on “Next” button to proceed.
Step3) Under “Manage Recovery Storage Group” section, click on “Create a recovery storage group” link.
Step4) Define the storage group that has to be linked to recovery storage group.
Step5) Now, enter a name for RSG, where its transaction logs and checkpoint files would be saved. Also, give a name of the database. Click on “Create the recovery storage group”.
Step6) Once RSG is created, updation regarding it will be available under “Results” section.
Note: To get details about RSG created, use Get-Mailbox Database command.
How To Mount Recovery Storage Group Exchange 2007
Now, in order to mount RSG to Exchange Server, click on “Mount or dismount databases in the recovery storage group” under Manage Recovery Storage Group Section
Select RSG that has to be mounted to the Server and click “Mount Selected Database”
Note: Once Recovery Storage Group is created and mounted to Server, restore mailbox database backup to it.
How To Recover Mailbox from RSG Exchange 2007
To restore database from RSG, Restore-Mailbox cmdlet can be used. This cmdlet helps to copy mailbox database from RSG to any Exchange 2007 Server within organization that has quality space and resource available to accommodate mailboxes. The standard cmdlet for restoring RSG is:
Limitations of Recovery Storage Group
To overcome these limitations of RSG, Exchange database recovery solution can be adopted. The tool allows recovery of mailboxes and public folders from Exchange EDB files to PST, MSG, EML file, and to another Exchange Server (higher version).