The Recovery Storage Group

In this article, I'm going to have a look at another new feature of Exchange 2003. This time, it's the Recovery Storage Group. Microsoft provides a full whitepaper on this particular feature, which has been posted to this blog quite recently. Here I will cover the key elements of the Recovery Storage Group - be sure to check out the whitepaper for in-depth information.

What is the Recovery Storage Group?

The Recovery Storage Group (RSG) is a new type of storage group in Exchange 2003 that essentially allows you to mount a copy of a mailbox store onto a production Exchange 2003 server. You can then recover data within the restored mailbox store whilst the current store is still running. Use of the RSG on a production server won't interfere with the users as the RSG is logically isolated; users cannot log into it, and mail cannot be delivered to it. As you can probably guess, the main benefit here is that you don't necessarily need a spare disaster recovery server in its own Active Directory forest to recover a single mailbox or single mailbox store, as was required in Exchange 2000.

Also, one other benefit of the RSG is something that is referred to as a "dial tone recovery strategy". The idea here is to create a brand new blank database in the event of problems with the production database. This way, your users are up and running much quicker and can send and receive new messages straight away. The failed production database can then be restored to the RSG, the old data extracted using ExMerge, and then transferred back into the users' mailboxes. Of course, once the production database is available again, it makes sense to put the temporary dial tone database into the RSG and recover the data from this database, since it will be much smaller than the restored production database.

Creating the RSG

This is basically the same as creating a new storage group. One thing to note is that you can still create a RSG even if you currently have the maximum number of 4 storage groups already created. Within Exchange System Manager, navigate to your target server object. Then, right-click the server on which you wish to install the RSG and choose New / Recovery Storage Group. You will then be presented with the following screen:

Creating a new RSG

Give the RSG a suitable name and also enter suitable transaction log and system path locations. Obviously, you will want to ensure that you enter different locations than those of the transaction logs belonging to the original storage group. One useful piece of information here is that, although you don't really need that much disk space for the location of the transaction log and system path locations, the paths specified here become the default location for the restored mailbox store files as well. I'll show you how to make sure you remember to modify the location of where you're going to restore your mailbox store files to a little later on. Click OK, and the RSG will now be created.

Newly created RSG

Also note that if you now bring up the properties of the newly created RSG, you will notice that the log file prefix field has been filled in with R00; this becomes the prefix used for the transaction logs within the RSG in the same way that the default first storage group uses a prefix of E00 for its transaction logs.

Adding a Mailbox Store

Now we need to add the desired mailbox store to the RSG. To do this, just right-click the RSG in ESM and choose Add Database to Recover. The following screen will be presented:

Choose your mailbox store

You'll see from this screen shot that you can add Exchange 2003 and Exchange 2000 SP3 mailbox stores to the RSG. However, note that these stores must be from servers within the same Administrative Group. Nonetheless, the ability to add an Exchange 2000 SP3 mailbox store is a really useful feature. Be warned, though, that once you add an Exchange 2000 SP3 mailbox store to a RSG, the mailbox store is upgraded to the same version as mailbox stores running on the server with the RSG. Therefore, you will not be able to copy this mailbox store back to its original server without upgrading that server to the same Exchange version as was in use on the server with the RSG. The method to extract data is then via ExMerge, which I'll cover later on. Also, you'll see that only mailbox stores are presented as possibilities to add to the RSG - public folder stores cannot be created in the RSG.

Once you've selected your chosen store, just click OK. The properties of that mailbox store are then presented as shown below. If you click the Database tab, you'll notice that the default location for where the store files will be recovered to is the same as that of the RSG you previously created. As I said earlier, this may be a problem, since it is likely that if you accepted the defaults during the creation of the RSG, your chosen location may not have enough disk space to hold the entire restored mailbox store. Now is the time to change the locations if disk space is an issue.

Changing the database paths

Other important things to note are that, by default, the newly added database should be dismounted. Also, if you bring up the properties of this database in the RSG and click the Database tab, you should notice that the Do not mount this store at start-up check box is automatically checked and is also greyed out. This is a feature of the RSG. Databases cannot be set to automatically mount; they must be mounted manually by the administrator. Also, the This database can be overwritten by a restore check box should be selected.

Restoring The Mailbox Store

This process should be the same as per any normal mailbox store restore process really. I'm not going to go into massive detail here, as restoring a mailbox store can potentially be a large subject, and this article is already large enough! In my example here, I'm going to be using the Windows Backup utility. As you can see, I've elected to restore the logs and mailbox store from my backup. The good thing about performing these online restores is that the RSG should automatically be detected by the backup utility. I also chose to have a hard recovery performed by selecting the Last Backup Set option in the Windows Backup utility.

Restoring the database

Once the database has been restored, it will be mounted if you select the option to mount it after the restoration process. I chose not to, and mounted it manually. However, the result is the same. Here's the restored and mounted database. Admittedly, this one doesn't contain much information!

The restored database

Extracting The Data

The ExMerge utility is used to extract data from the RSG mailbox store. Note though, that the only supported interface for extracting this data is via the Exchange 2003 version of ExMerge. You can find this version of ExMerge at the Exchange 2003 site here. I won't make this article any longer than it needs to be by posting lots of screen dumps of each ExMerge screen that you encounter as you proceed with the utility. The main screen that's of interest here is the Database Selection screen, since it is important that you choose the Recovery Storage Group. After doing this, you will be presented with a list of mailboxes held in the mailbox store in the RSG which you can then export to PST. It's that easy.

Extracting data via ExMerge

The RSG is an excellent utility for recovering single mailboxes or mailbox stores. It isn't a replacement for sound disaster recovery processes though.

Account Deleted on December 23, 2003 at 06:57 AM in Useful Info
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i like it but hot to get the software

Posted by: vikki at Oct 23, 2004 11:06:35 PM

I would recommend taking a look at Power Controls sold by Ontrack Data Recovery.

I use it and it is great timesaver. I don't ever have to do a brick-level backup again.

Posted by: Peter Low at Jan 3, 2005 2:09:46 PM

Thank you for the nice explanation about the data recovery. I didn't know that the Windows had so powerful tools for this purpose.

Posted by: Trooper at Jul 23, 2007 4:11:12 AM

Very useful explanation thank you!

Posted by: Howie at Aug 1, 2007 12:57:24 AM

This is a really interesting read, anybody know how to do all of this with Exchange 2007? I've come up with a problem where the mailbox GUID in the Live Mailbox Database does not match GUID in the RSG Mailbox database. Without Exmerge in 2007 I am at a loss. Any help would be appreciated.

Posted by: Giles at Aug 31, 2007 3:13:39 AM

sounds great, I must be missing something because when I try to restore it does not pickup my recovery storage group and goes into the original location - what am I missing?

Posted by: Monica at Nov 19, 2007 4:54:15 PM

The article is vey helpfull fo me .Thanks a lot.

Posted by: Rajashree Upadhyaya at Jan 12, 2008 6:14:38 PM

nice explanation

thank you!

Posted by: sufiyan at Jan 18, 2008 5:20:47 AM

Nice explanation
I hope to see another critical topics explanation

Good Job

Posted by: Mohanad at Jun 30, 2008 12:09:34 AM

Very Good One..............

Posted by: Gautham at Mar 23, 2010 1:08:32 PM

Nice & Usefull Explaination,
Thank You!

Posted by: naresh at Nov 16, 2010 11:35:11 PM