Windows Server 2003 : Fundamentals of Backup

At the core of every backup procedure is a backup tool and a backup plan. Windows Server 2003 provides a robust, flexible utility called Ntbackup. Ntbackup supports much of the functionality found in third-party tools, including the ability to schedule backups, and interacts closely with VSS and the Removable Storage Management (RSM) system.

Introducing the Backup Utility

The backup utility in Windows Server 2003, commonly referred to by its executable name, Ntbackup, can be opened by clicking Backup in the Accessories-System Tools program group in the Start menu. Alternatively, it can be launched by typing ntbackup.exe in the Run dialog box.

The first time you launch the backup utility, it runs in Wizard mode, as shown in Figure 1.If you agree with most administrators that it is easier to use the standard utility than the wizard, clear the Always Start In Wizard Mode check box, and then click Advanced Mode.

Figure 1. The Backup Or Restore Wizard

As you can see on the utility’s Welcome tab in Figure 2, you can back up data manually (the Backup tab) or using the Backup Wizard. You can also schedule unattended backup jobs. The Backup Utility is also used to restore data manually (the Restore And Manage Media tab) or using the Restore Wizard. The Automated System Recovery (ASR) Wizard, which backs up critical operating system files.

Figure 2. The Welcome tab of the Backup Utility

This lesson focuses on data backup planning and execution, and to explore the capability of the Backup Utility we will use the Backup tab, as shown in Figure 3, rather than the Backup Wizard.

Figure 3. The Backup tab of the Backup Utility

Selecting Files to Back Up

You may use the Backup tab to select the files and folders to be backed up. Items may be on local volumes or in network folders. When you select an entire folder for backup, a blue check mark appears. If you select only certain items in a folder, the folder displays a dimmed check mark to indicate a partial backup.

To back up files or folders from remote machines, either select the items from a mapped drive or expand My Network Places. The latter is the equivalent of using a Universal Naming Convention (UNC), such as \\Server01\Sharename\Path-to-resource. Although selecting files and folders through My Network Places is more cumbersome (you must navigate more levels of the interface to locate the files), it has an advantage because drive mappings are more likely to change over time than UNCs.

Tip

You can save the set of selected files and folders using the Save Selections command in the Job menu. You can later load the selections using Load Selections from the Job menu, saving the time required to recreate your selection.

Selecting the Backup Destination

Windows Server 2003 allows you to create a backup job on a variety of media types: a tape drive, a removable drive such as the Iomega Jaz drive, and, most importantly, directly to file on a disk volume. If the destination is a tape, the name specified must match the name of a tape that is mounted in the tape device.

If backing up to a file, the Backup Utility creates a .bkf file in the specified location, which can be a local volume or remote folder. It is not uncommon for administrators using the Backup Utility to back up a file on each server and consolidate the resulting files on a central server, which then transfers the backups to removable media. To achieve such a consolidation, the backup destination is configured as either a UNC to a single location on a central server or a local file on each server, which is later copied to a central location.

There are two important limitations of the Backup Utility. First, it does not support writable DVD and CD formats. To work around this limitation, back up to a file, then transfer the file to CD or DVD. Second, backing up to any destination except a file requires that the target media be in a device physically attached to the system. This means, for example, that you cannot back up data to a tape drive attached to a remote server.

Determining a Backup Strategy

After selecting the files to back up and specifying the backup destination, there is at least one more critical choice to make. Click Start Backup, then click Advanced, and the Advanced Backup Options dialog box appears, allowing you to specify the backup type. The backup type determines which of your selected files is in fact transferred to the destination media.

Each backup type relates in one way or another to an attribute maintained by every file: archive. The archive (A) attribute is a flag that is set when a file has been created or changed. To reduce the size and duration of backup jobs, most backup types will only transfer to media the files that have their archive attribute set. The most common source of confusion regarding the archive attribute arises from terminology. You will frequently hear, “The file is marked as backed up,” which really means that the archive attribute is cleared after a particular backup job. The next job will not transfer that file to media. If the file is modified, however, the archive attribute will again be set, and the file will be transferred at the next backup.

Exam Tip

As you explore each backup type, keep track of how the archive attribute is used and treated by the backup type. You will need to know the advantages and disadvantages of each backup type and how to fully restore a data structure based on the backup procedures that have been implemented.

Normal Backups

All selected files and folders are backed up. The archive attribute is cleared. A Normal backup does not use the archive attribute to determine which files to back up; all selected items are transferred to the destination media. Every backup strategy begins with a Normal backup that essentially creates a baseline, capturing all files in the backup job.

Normal backups are the most time-consuming and require the most storage capacity of any backup type. However, because they generate a complete backup, normal backups are the most efficient type from which to restore a system. You do not need to restore multiple jobs. Normal backups clear the archive attribute from all selected files.

Incremental Backups

Selected files with the archive attribute set are backed up. The archive attribute is cleared. Selected files with the archive flag are transferred to the destination media, and the flag is cleared. If you perform an incremental backup one day after a normal backup has been performed, the job will contain only the files that were created or changed during that day. Similarly, if you perform an incremental backup one day after another incremental backup, the job will contain only the files that were created or changed during that day.

Incremental backups are the fastest and smallest type of backup. However they are less efficient as a restore set, because you must restore the normal backup and then restore, in order of creation, each subsequent incremental backup.

Differential Backups

Selected files with the archive attribute set are backed up. The archive attribute is not cleared. Because a differential backup uses the archive attribute, the job includes only files that have been created or changed since the last normal or incremental backup. A differential backup does not clear the archive attribute; therefore, if you perform differential backups two days in a row, the second job will include all the files in the first backup, as well as any files that were created or changed during the second day. As a result, differential backups tend to be larger and more time-consuming than incremental backups, but less so than normal backups.

Differential backups are significantly more efficient than incremental backups as a restore set, however. To fully restore a system you would restore the normal backup and the most recent differential backup.

Copy Backups

All selected files and folders are backed up. Copy neither uses nor clears the archive attribute. Copy backups are not used for typical or scheduled backups. Instead, copy backups are useful to move data between systems or to create an archival copy of data at a point in time without disrupting standard backup procedures.

Daily Backups

All selected files and folders that have changed during the day are backed up, based on the files’ modify date. The archive attribute is neither used nor cleared. If you want to back up all files and folders that change during the day without affecting a backup schedule, use a daily backup.

Combining Backup Types

Although creating a normal backup every night ensures that a server can be restored from a single job the next day, a normal backup may take too much time to create, perhaps causing the overnight job to last well into the morning, thus disrupting performance during working hours. To create an optimal backup strategy, you must take into account the time and size of the backup job, as well as the time required to restore a system in the event of failure. Two common solutions are:

• Normal and differential backups On Sunday a normal backup is performed, and on Monday through Friday nights, differential backups are performed. Differential backups do not clear the archive attribute, which means that each backup includes all changes since Sunday. If data becomes corrupt on Friday, you only need to restore the normal backup from Sunday and the differential backup from Thursday. This strategy takes more time to back up, particularly if data changes frequently, but is easier and faster to restore, because the backup set is on fewer disks or tapes.

• Normal and incremental backups On Sunday a normal backup is performed, and on Monday through Friday incremental backups are performed. Incremental backups clear the archive attribute, which means that each backup includes only the files that changed since the previous backup. If data becomes corrupt on Friday, you need to restore the normal backup from Sunday and each of the incremental backups, from Monday through Friday. This strategy takes less time to back up but more time to restore.

Practice: Performing Different Backup Types

In this practice, you will create several backup jobs, examining the role of the archive attribute.

Exercise 1: Create Sample Data

1.	Open Notepad and create a text file with the following lines. Type each line carefully. md c:\Data net share data=C:\Data md c:\Data\Finance cd c:\data\Finance echo Historical Financial Data > Historical.txt echo Current Financials > Current.txt echo Budget > Budget.txt echo Financial Projections > Projections.txt
2.	Save the file as “c:\createfiles.bat” including the quotation marks.
3.	Open the command prompt and type cd c:\.
4.	Type the command createfiles.bat.
5.	Open Windows Explorer and navigate to the c:\data\finance directory. You should see the following display:
6.	If the Attributes column is not visible, right-click the column headers Date Modified and select Attributes. The archive attribute is displayed. Note Leave Windows Explorer open on C:\Data\Finance. You will refer to it throughout this practice.

Exercise 2: Perform a Normal Backup

1.	Open the Backup Utility by running Ntbackup.exe from the command line, or selecting Backup from the Accessories–System Tools group on the Start menu.
2.	Clear the Always Start In Wizard Mode check box.
3.	Click Advanced Mode.
4.	Select the Backup tab.
5.	Expand My Computer, the C drive, and then the Data folder so that you can select the Finance folder. The Finance folder has a blue check mark, meaning a complete backup, whereas its parent folder has a dimmed check mark, indicating a partial backup. Any files added to the Finance folder will be included in the backup, but any files added to the Data folder will not.
6.	On the Job menu, choose Save Selections.
7.	Save the selections as Finance Backup.bks.
8.	In the Backup Media Or Filename box, type c:\backup-normal.bkf. Note In production environments you will be likely to use removable media for backups, but to keep hardware requirements to a minimum, practices in this lesson will back up and restore using local files. If you have access to a tape drive, feel free to use it during these practices.
9.	Click Start Backup and then click Advanced.
10.	Confirm that Normal is selected in the Backup Type drop-down box, and then click OK.
11.	Select Replace The Data On The Media With This Backup and click Start Backup.
12.	Observe the Backup Progress dialog box. When the backup is complete, click Report.
13.	Examine the report. No errors should be reported.
14.	Close the report and the Backup Utility. Note that in Windows Explorer, the Attributes column no longer shows the archive attribute.

Exercise 3: Perform Differential Backups

1.	Open C:\Data\Finance\Current.txt and add some text. Save and close the file.
2.	Examine C:\Data\Finance in Windows Explorer. What files are showing the archive attribute? Only the one you just changed.
3.	Open the Backup Utility and click the Backup tab.
4.	From the Job menu, choose Load Selections to load Finance Backup selections.
5.	In the Backup Media Or Filename box, type c:\backup-diff-day1.bkf.
6.	Click Start Backup.
7.	Click Advanced and select Differential as the backup type.
8.	Start the backup and, when complete, confirm that no errors occurred.
9.	Close the Backup Utility.
10.	Examine the folder in Windows Explorer. Which files have their archive attribute set? The file Current.txt is still flagged for archiving.
11.	Open the Budget file and make some changes. Save and close the file. Confirm that its archive attribute is now set.
12.	Repeat steps 3 through 9, creating a backup job in the location: c:\backup-diff-day2.bkf. Be sure to look at the resulting backup report. How many files were copied for the backup? Two.

Exercise 4: Perform Incremental Backups

1.	Open the Backup Utility and click the Backup tab.
2.	From the Job menu, choose Load Selections to load Finance Backup selections.
3.	In the Backup Media Or Filename box, type c:\backup-inc-day2.bkf.
4.	Click Start Backup.
5.	Click Advanced and select Incremental as the backup type.
6.	Start the backup and, when complete, confirm that no errors occurred.
7.	Close the Backup Utility.
8.	Examine the folder in Windows Explorer. Which files have their archive attribute set? None.
9.	Open the Projections file and make some changes. Save and close the file. It should show the archive attribute in Windows Explorer.
10.	Repeat steps 1 through 8, creating a backup job in the location: c:\backup-inc-day3.bkf.