The main concept that you need to understand regarding Exchange Server is that all of the mailboxes, public folders,
calendars and other types of data are stored within databases.
The reason why this concept is important is because Exchange keeps these databases open at all times and as you probably know, you can't usually back up an open file.
There are two ways around the problem: You can perform either an online backup or an offline backup.
An offline backup is one in which you shut down all Exchange-related services and then back up the server using a normal, file-level backup. An offline backup will get the job done, but the problem is that the server is inaccessible during the backup. The other problem is that if the Information Store service fails to shut down for some reason, then you will be backing up open files and your backup will be invalid.
The preferred method of backing up Exchange is an online backup. The main idea behind an online backup is that Exchange is running during the backup and therefore, users continue to have access to Exchange resources even while the backup is running.
The trick to being able to perform an online backup is that your backup software must be Exchange Aware. Most of the companies that make server grade backup software offer an Exchange Server add on, but they typically charge a premium price for it. If such an add on is beyond your budget, then you will be happy to know that when you install Exchange Server, the Setup program modifies the Windows Backup program to make it Exchange Aware.
The reason why an Exchange aware backup program is able to back up an Exchange Server while other types of backup programs are not is because of the way that Exchange works with transaction logs. While it's true that Exchange does keep the databases open at all times, modifications (such as new mail messages) are not written directly to the databases. Instead, the modifications are written to the transaction logs, which are then later copied to the databases.
'Exchange aware' advantages
When you backup an Exchange Server with an Exchange aware backup program, the backup software commits the contents of the transaction logs to the Exchange databases and then guarantees that no more changes will be made to the database during the backup. Any changes that occur during the backup are simply written to the transaction logs that will be backed up later.
Backing up an Exchange Server is simple. If you look at the Backup tab of the Windows Backup utility, you will notice that just below the My Computer and My Documents options, there is a Microsoft Exchange Server option. Simply expand this option and you will see a list of the organization's Exchange Servers. You can then expand the servers that you want to back up and then choose to back up either the entire Information Store or a particular storage group within the Information Store.
Restoring an Exchange Server is just as easy, assuming that you are restoring an entire storage group or Information Store.
Just select what you want to restore and click the Start Restore button. Depending on the backup software that you are using, you may have to tell Exchange that you want to allow a database to be restored. To do so, open the Exchange System Manager and navigate to Administrative Groups | your administrative group | Servers | your server | storage group | store. Right click on the store that you plan to restore and select the Properties command from the resulting shortcut menu. When you do, you will see the store's properties sheet. Select the Properties sheet's Database tab and then select the This Database Can Be Overwritten By A Restore check box and click OK.
The problem with the Windows Backup utility is that Microsoft doesn't give you any direct method of restoring an individual mailbox (also referred to as a brick level restore).
The easiest way to restore an individual mailbox is to buy an Exchange aware backup program that supports brick level restore operations. If that isn't an option for you, then there are a couple of other ways to accomplish a brick level restore, but they aren't easy.
In Exchange 5.5, the easiest way to perform a brick level restore without the aid of special software was to restore your backup to an empty server and then set up a workstation to connect to that server. You can then open the user's old mailbox in Outlook, dump the mailbox contents to a personal folder (a PST file) and then save the PST file to a CD. You would then take the CD to the user's computer and have them open the PST file and copy the necessary data to their Exchange mailbox.
In Exchange 2000 and 2003, the easiest way to perform a brick level restore is to use the ExMerge utility.
ExMerge is a utility that is designed for Exchange server migrations, but it works well for brick level restores as well. The idea is that you can run an automated ExMerge just after your normal Exchange backup. You can direct ExMerge to dump each mailbox's contents to a PST file. You can then back up those PST files. If your users ever need to restore deleted items to their mailboxes, they can open their PST file and copy the necessary items.
Brien M. Posey, MCSE, is a Microsoft Most Valuable Professional for his work with Windows 2000 Server and IIS. Brien has served as the CIO for a nationwide chain of hospitals and was once in charge of IT security for Fort Knox. As a freelance technical writer he has written for Microsoft, CNET, ZDNet, TechTarget, MSD2D, Relevant Technologies and other technology companies. You can visit Brien's personal Web site at http://www.brienposey.com.
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