Volume Shadow Copy Service

Microsoft Volume Shadow Copy Service (VSS) isn't sliced bread, but for file backup and restoring, it might be the next best thing. VSS, which ships with Windows Server 2003, creates a point-in-time copy of files stored in shared network folders—even files that are open or locked. Applications can continue to write data to the disk volume during the shadow copy process, which eliminates the need to perform backups before or after business hours. Additionally, a volume copy backup lets users perform file restores, minimizing administrative overhead for basic restore operations.

Configuring VSS is straightforward. Right-click the volume on which the network shares reside, then select Properties to open the configuration window. Click the Shadow Copies tab, then click the volume you want to back up. Click Enable to enable a shadow copy of all shares on the volume and create the first backup. Figure 1 shows the Shadow Copies tab with shadow copy enabled. On this tab, under Select a volume, you can see the next copy runtime, the number of shares on the volume, and the amount of disk space that the shadow copy function is using. Under Shadow copies of selected volume is a list of copies of the selected volume. To create additional copies, click Create Now. You can stop the shadow copy creation process by clicking Disable, but be aware that doing so deletes any copies you've already created.

To configure other VSS settings, click Settings on the Shadow Copies tab. On the Settings dialog box, which Figure 2 shows, you can configure the maximum disk space for the shadow copies. Click Schedule to specify when VSS runs. By default, VSS runs twice every weekday, at 7:00 a.m. and 12:00 p.m. Click Schedule to open the Schedule dialog box, in which you can view scheduled backup times and configure new backup times. Click New to add new backup times, click Delete to remove scheduled times, and click Advanced to configure advanced schedules. The scheduling feature of the VSS function allows granular control, but I recommend that you try to avoid scheduling copies more frequently than once per hour.

VSS can ease the administrative burden by transferring certain tasks to users, but to take advantage of this functionality, client software is required. This client software is the Previous Versions Client (twcli32.msi), which you can find on your Windows 2003 server in the windows\system32\clients\twclient\x86 folder. You can run the .msi file to install the client manually, or use Group Policy or a software deployment application such as Microsoft Systems Management Server (SMS) to push the client to your corporate workstations. The installation is simple and requires no additional configuration. To uninstall the client, simply run the .msi file again.

With the client installed, your users can access previous versions of files on network shares. To access previous versions of files, right-click the applicable network share and select Properties. Next, select the Previous Versions tab, as Figure 3 shows. From this tab, select a volume copy, then click View to see the contents of the backup. The backup file opens in a standard Windows Explorer window. You can then choose files you want to reinstate and copy them to the appropriate network share. You can also click Copy to copy the entire backup to another location, or click Restore to restore the entire network share backup.

The Previous Versions Client gives users with Modify permissions to a network share the power to restore deleted or older versions of their files without administrative intervention. However, this feature is a double-edged sword that requires user training to ensure proper use.

VSS doesn't eliminate the need for full and regular backups. This functionally provides richer backup capabilities and offers autonomy to end users but still requires a strong backup strategy to protect the data and system information on your server. Additional information about VSS is available in the Windows 2003 Help and Support files.

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