Backup is paramount, especially when e-mail is concerned. As an Exchange Administrator, you will be tasked with ensuring daily backups are performed and verified, and if it comes to the worst, with disaster recovery. Having the e-mail system go down for a few hours while you restore from a backup is a fair compromise when compared with the potential damage caused by loss of data. As an Exchange Administrator, you need to be familiar with the what, when and how of Exchange backup.
Types of Backup
There are four different backup types you can use with Exchange 2007 and you will likely choose a combination of these depending on backup capacity, frequency and restoration requirements. The four available backup types are:
Full backup - backs up the entire database file and associated transaction logs. When complete, it verifies the integrity of the database and the transactions logs are purged.
Copy backup - almost identical to full backups except for the fact that the transaction logs are not purged once the backup is complete.
Incremental backup - backs up only the changes to the database since the last full or incremental backup.
Differential backup - backs up only the changes to the database since the last full backup and the transaction logs are not purged once the backup is complete.
Note: All the above backup types should be performed against the production database.
Warning: Always test your backups! You probably heard this a thousand times before so hopefully it is drilled into your mind. It is highly important that you confirm the data you have backed up can restore properly. What good is backed up data that cannot be restored?
What should I backup?
As a minimum, the following should be backed up:
The System State which includes Active Directory information where all Exchange Server configuration is stored.
The ..\Program Files\Microsoft\Exchange Server directory (with the exception of the Mailbox\<Storage_Group> folders).
The mailbox and public folder databases
Apart from this, you may also consider backing up the following items which will help you rebuild a server in the event of a complete failure:
How often should I backup?
You should draw up a schedule listing when each type of backup will be performed. There is no fixed rule as to how often this should happen but depends on your company policy (and the defined recovery point objective). However, I do recommend you perform a full backup once a week at the very least, and every night if you have resources available that allow you to do so. Since every backup consumes a certain amount of system resources in terms of CPU, RAM, HDD and Network bandwidth, it is important that backups are performed at non-peak hours and before online maintenance kicks in (which by default is set to start daily at 01:00am).
Note: The Recovery Point Objective is the point in time to which you must be able to recover data and is considered by your company as an acceptable loss in the event of a disaster. For example, an RPO of 8 hours means you must perform a backup every 8 hours.
Local Continuous Replication (LCR)
Local Continuous Replications is a new type of "backup and recovery" method in Exchange 2007 that allows you to keep a replicated copy of the current database on the local server. This way, if the production database becomes corrupt, the Exchange Administrator can quickly and easily switch over to the LCR database copy. The advantage of this method is that it reduces the time it takes to restore a database from backup. So how would I know if my database is corrupt? Well, probably the best place to go to find out would be the Event Viewer. In some cases, you'll notice that normal backups of the production database fail or the database will report errors when you attempt to mount it. Corruption may also occur during normal operation when a single page of data is corrupt and the database engine fails to read it. Again, in these cases you'll most likely see an event log indicating this in the Event Viewer.
Before implementing LCR, consider the following:
Storage groups can only have one mailbox database or public folder database each
Tip: If you wish to replicate more than one public folder database you can make use of public folder replication instead.
With LCR enabled, the system CPU and Memory consumption will increase by about 30-40 %, so ensure that the server you enable it on can handle the load. If you deem necessary, consider moving some mailboxes or server roles to another server.
For best performance, point the LCR database and transaction logs to another physical disk and ensure that the drive on which the LCR database is to be stored can handle the same I/O throughput and has enough free space to store the database and transaction logs.
To implement LCR, do the following:
From the Exchange Management Console, navigate to Server Configuration | Mailbox
Highlight the server name from the top half of the pane. Highlight the storage group in the Actions pane and click "Enable Local Continuous Replication".
On the first page of the wizard, simply confirm the name of the storage group and database that will be configured for Local Continuous Replication.
Next, browse to the path where the system files and replication log files will be stored, followed by selecting the Exchange database file path in the third page of the wizard.
Now confirm the configuration options in the "Enable" page and click the Enable button to proceed.
You will know LCR is enabled on the storage group because an arrow will appear on top of the usual storage group icon, as shown in the image below:
Finally, to check the status of LCR, go to the properties of the Storage Group and select the "Local continuous replication" tab.
In part 2 of this series, we will look at how to restore an LCR database in the event that your production database goes down.
Backing up Exchange using the Windows Backup Utility
Despite the many third-party Exchange online backup software packages available on the market today, the Windows Backup Utility (ntbackup.exe) remains popular because it can do a pretty good job, especially for small to medium sized businesses. It's free too! The instructions below will demonstrate how to backup an Exchange database (and related files) using ntbackup.exe.
The first thing you need to do is launch the Windows Backup Utility. To do this, either navigate to Start | Programs | Accessories | System Tools | Backup or type ntbackup.exe from the Run window.
If the wizard pops up uncheck the "Always start in wizard mode" option, close the wizard and open the Window Backup Utility again so it starts in advanced mode.
From the Backup tab, select the elements you want to be backed up, such as "Microsoft Information Store", "System State" and the "Exchange Server" program files location. Select all folders in the "Exchange Server" directory, except for the storage group locations (we're taking care of these when selecting the "Microsoft Information Store" in step (2)).
Finally, choose a backup destination and media or file name location and press "Start Backup". You will then be asked to specify the backup job information. Choose "Append this backup to the media" to add the current backup to the previous data or "Replace the data on this media with this backup" to wipe the previous data and add the current backup data instead. You can choose to schedule the backup to occur at a later date by clicking the "Schedule" button. The "Advanced" button will allow you to configure advanced options such as choosing the backup type and verifying the data after a backup.
Once you have configured your desired options, press Start Backup or simply allow the schedule to take over and initiate the backup at the specified time.
In part 2 of this series, we will look at how to restore an Exchange database (and related files) using the Windows Backup Utility.
Conclusion
In this article we looked at the different types of backups available, backup schedules and Local Continuous Replication (LCR) as well as how to use the Windows Backup Utility to backup Exchange 2007. In part 2, we'll talk about the methods for recovery with LCR and the Windows Backup Utility, as well as how to plan for a disaster, steps you can take to help prevent a disaster and how to recover deleted items or deleted mailboxes in Exchange 2007.
References
Database Backup and Restore (TechNet)
How to Perform a Basic Backup of Exchange Databases (TechNet)