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Geek of all TradesThe Benefits of Big, Cheap Disks

Greg Shields



Using WSB to Back Up Hyper-V Virtual Machines
WSB can back up virtual machines hosted atop a Windows Server 2008 computer running the Hyper-V role. Virtual machines in Hyper-V that leverage high availability with Windows Failover Clustering tend to operate with a single virtual machine per volume, making WSB's volume-centric backups useful for per-VM protection.
Using WSB to back up virtual machines requires enabling the VSS Writer for Hyper-V. To do this, create a REG_SZ key named Application Identifier with a value of Hyper-V in the registry at the location

HKEY_LOCAL_MACHINE\Software\Microsoft \Windows NT\CurrentVersion\WindowsServerBackup\ Application Support\{66841CD4-6DED-4F4B-8F17- FD23F8DDC3DE}.

Be aware that virtual machines that contain dynamic disks cannot be backed up by WSB. Virtual machines that do not include support for VSS backups—such as Windows 2000, Windows XP, or virtual machines that do not have Integration Components installed—cannot be backed up using WSB. Lastly, be cautious with the use of snapshots, as virtual machines that contain two or more snapshots will fail to restore.
I was reminded of this recently while thinking about the Microsoft Windows Server Backup (WSB) utility and how backup has changed. WSB is found in Windows Server 2008 and it finally brings reliable whole-system restores to small businesses and environments—right within the server OS. The utility introduces some new—and not always obvious—ways of architecting backups for your Windows environment.
Unfortunately, since its introduction, this backup tool has also come in for some negative press: its files are incompatible with those from its NTbackup predecessor; backups are scoped at the volume level only; system-state backups are much larger than before; and backup tapes are not supported. But these items actually reflect deliberate design decisions based on the way storage has evolved.
Today, disk-to-disk backups make far more sense than disk-to-tape for the jack-of-all-trades IT professional, due primarily to the cost and ease of use of today's USB-connected external disks. Since my first sight of that terabyte, the size and cost of disk storage has shrunk to the level of absurdity. Only a few short years later, we in IT saw terabyte capacity reduced from refrigerator-size to merely being striped across a few hard disks in a single server. Now, even consumers can buy that same terabyte, bundled into a 5" x 6" x 2" form factor for around a hundred bucks. Disks these days are indeed huge and cheap.
Which brings us to why forcing backups to occur at the volume level makes sense—it allows entire computers to be quickly backed up with a few mouse clicks. Volume Shadow Copy Service (VSS) integration with the residing OS means that no files are missed during a backup pass. Integrating backups with Microsoft's WinPE enables a dismounted OS to assuredly return a failed computer back to working order—without the multiple install-the-operating-system-and-then-restore-over-the-top steps of yesterOS. Each of these new capabilities works best when backups are accomplished from server hard drive to USB disk, rather than to traditional tape devices. And, best of all, each of these is available for no added cost with your existing server OS.


Incorporating WSB
To add WSB functionality to an existing server, you must install it through Server Manager. There are three items to install: Windows Server Backup, Command-line Tools, and Windows PowerShell, which are available in the Add Features Wizard in Server Manager.
After the installation, you will interface with WSB through Server Manager's Storage node, where you'll also find the Recover option for restoring files and a selection for configuring performance settings (see Figure 1). You can choose to perform either a one-time backup of a server or a scheduled backup and, when choosing, you'll notice two of WSB's "new" behaviors. First, if you select to Backup Once, you'll be presented with a list of volumes to back up. You'll immediately notice that WSB will not back up individual files and folders, only entire volumes.

Figure 1 The Windows Server Backup Console
If you continue through the Backup Once wizard, you'll be asked for the local storage drive or remote folder to use as a backup target, as well as an advanced option whose setting determines whether you want application settings to be retained and the VSS archive to be kept or updated. When you complete the wizard, the backup will begin, starting first with a VSS snapshot to ensure the successful backup of any locked files.
These single-instance backups are considered to be the solution for one-time needs, and thus you are allowed to target backups to a remote folder across the network. This is not possible, however, when backups are configured to operate on a schedule. In that case, you'll no longer find a GUI option for targeting backups to a remote folder (see Figure 2). You are permitted only to back up the server to an attached disk that is not already an OS or application volume.

Figure 2 Scheduled backups in WSB are scoped to the volume, not the individual file or folder
The reason for this new behavior lies in how WSB treats the disks you attach for regular backups. With scheduled backups, WSB thinks of its targets as dedicated devices for regular use. Any target disk is automatically formatted as the schedule is created. Once formatted and targeted for a scheduled backup, that disk is no longer exposed in Windows Explorer. This prevents the accidental overwrite of data by a careless administrator and effectively locks the disk for use by WSB alone. The disk is treated essentially as tape devices were, but disks offer many advantages over tapes, particularly for the small business or organization. These days, external drives are cheaper, faster, and easier to use than tape. And that's not all.
First, WSB's disk-based solution enjoys a significant reduction in complexity with incremental backups. WSB's integration with VSS means that backups start with the creation of a snapshot of the source volume. Later backups are completed through block-level incrementals that require only the processing of changes since the last backup. This is much different from tape-based backup, where incrementals are stored elsewhere on the backup tape, or on completely different tapes, requiring increasing quantities of storage as well as increasing amounts of time to complete a restore. Finally, once you set up a scheduled backup to a dedicated disk, WSB will automatically keep as many backup versions as possible for the storage and does not require you to intervene when the backup target is full. Instead, it automatically deletes the oldest backup to make space for the newer backups.


Multiple Backup Disks
WSB lets you create extra backup disks by allowing additional disks to be plugged in prior to a server's scheduled backup time. This means you can rotate one set of backup drives off-site for protective restore in the case of a disaster or electrical malfunction.
To add another dedicated disk to an existing server backup, first configure and run a scheduled backup to an attached and dedicated device. When it's done, click the Backup Schedule link again to start the wizard. When prompted, select Modify Backup and navigate to the screen titled Add or remove backup disks. Selecting Add more disks brings up the screen shown in Figure 3, where you can select the new disk on which to target the backup. As before, once the disk is targeted for a backup, it will be formatted and removed from visibility in Windows Explorer.

Figure 3 You can add a new dedicated disk to WSB for off-site rotation
Completing this step enables the secondary disk to be plugged into your server whenever you require a backup to be rotated off-site for storage. WSB will label the disk—much as tapes were traditionally labeled—with the correct markings (see Figure 4) so that the disk can be later identified. Your organization may also find reasons other than off-site storage to create backups to multiple disks. You may want one set to remain plugged into its corresponding servers to support individual file restores, or you may want one to be used for long-term archiving.

Figure 4 WSB’s Label for a Dedicated USB Disk


Managing Restores
As noted earlier, WSB does not perform backups of individual files. Whether you attempt a one-time or scheduled backup, WSB scopes that backup at the individual volume. Though this might initially seem like a limitation, it actually makes sense in terms of protecting the backup as a whole. And you can restore individual files.
Once backups have been configured for each of the servers in your environment, those backups remain online and available at all times, as long as the USB disk remains connected to the server. Restoring individual files from that USB disk's backup involves remotely connecting to that server's WSB console and selecting the Recover option. Then you simply select the date of the backup and the files to be restored. User files can be restored to their original location or alternate locations, and you can either overwrite existing files or create additional copies. Completing the wizard accomplishes the file restore from the attached USB drive.
The entire process is quick and without the traditional overhead associated with searching for the right tape, loading it into the tape device, scanning for the needed file, and ultimately restoring it. No longer will you be searching across multiple tapes, looking for the file you want to restore. Unlike tape backups, which can spread individual files across any number of tapes and require accurate cataloging and storage of the entire tape set, disk-based backups store the entire contents of the backup and all its incrementals in one place. If you've ever been unsuccessful in completing an individual file backup due to the loss or failure of a single tape in a set, the reliability of this feature will be much appreciated.
Disk-based backup and the use of VSS also improve the entire-server restoration process. Using volumes as the boundary of backups means that an entire server can always be successfully restored in the case of a loss or disaster. You can ensure this capability by making sure to back up each of the operating system and application volumes on your server. One-time backups also include a checkbox marked "Enable system recovery" that ensures all the right drives are checked.
Restoring a failed server with WSB is accomplished in a single step from the server's bare metal. It no longer requires the installation of a fresh operating system on top of which your restore will layer the backup's files. To restore a failed server, boot the server from the Windows Server 2008 DVD media and select Repair your Computer. Follow the prompts to begin a Complete PC Restore, selecting the USB disk as the source for the server's backup files. You can find the exact steps to do this at the Ask the Core Team blog.


Backup on a Budget
Admittedly, WSB may not be the right choice for large organizations. As shipped, it can't back up Exchange 2007 stores, although some third parties have developed integrations that can make this possible. While WSB can back up Hyper-V virtual machines, it can't back up connected disks within those virtual machines. Backing up just the system state of a domain controller requires a substantially larger amount of disk space than in previous versions.
On the other hand, many aspects of WSB make it extremely useful for the small-environment administrator. When used as part of a dedicated backup solution with lots of big, cheap USB disks, WSB can be an effective solution that fits the small environment budget. For more information, visit the Backup and Recovery Overview page of the Windows Server TechCenter.


Greg Shields, MVP, is a partner at Concentrated Technology. Get more of Greg's Jack-of-All-Trades tips and tricks at www.ConcentratedTech.com.