What is Windows Server Backup and how does it work on Windows Server 2008

The backup utility in Windows Server 2008 and Windows Vista (Business, Enterprise and Ultimate editions) uses Windows Server Backup, the new and improved replacement of the traditional method of backup, NTBackup, found in earlier Windows operating systems such as Windows 2000 and Windows 2003.

Windows Server Backup

Windows Server Backup makes use of a new block-level backup procedure which makes backing up and recovering windows servers to be a quick and efficient process. Conceptually, Windows Server backup is similar to differential backups where only the changed blocks are backed up. Effectively, this means that all successive backups are executed quickly since only a small percentage of the backup source will have changed blocks on a day to day basis. Using Microsoft’s Volume Snap Service (also known as Volume Shadow Copy), Windows Server backup is able to tell which blocks have changed and need to be backed up.

The following diagram illustrates the block-level backup process across three days, starting from a backup destination with no previous backups on it.

From the above illustration, you may notice that Wednesday’s backup file appears to be a full backup with the changed blocks from Wednesday, merged with the previous night’s (Tuesday) backup. Even though the backup that was performed on Wednesday only backed up a couple of changed blocks, the final backup file on the destination disk is a full backup file. This is because, due to the nature of the new block-level backup process, all backups after the initial full backup will always produce a backup file with the entire backup history.

Thus restoring backups created by Windows Server backup can be done in a couple of easy steps. Instead of having to restore the full backup and then any further incremental or differential as with the traditional backup methodology, users can perform bare metal restores or individual file and folder restores using the latest backup file on the backup device.

Another benefit of Windows Server Backup is that instead of backing up at a file level, it performs backups by creating block-level volume images. As a result, we can get rid of the usual overhead of opening and closing all files within a backup specification which occurs for all files in the traditional backup model, even if a file does not need to be backed up.

Windows Server backup also provides automatic disk space management such that disk space issues are eliminated. Older versions of backups are automatically discarded as the backup device runs out of space. Please note that this assumes the backup device is larger than the size of the backup selection.

Some important points to consider with regards to Windows Server Backup:

• Only entire volumes can be selected for backup. It is not possible to specify individual files and directories.
• As the backup file is a selective image, blank spaces, page files, hibernate files and other certain folders are not backed up.
• The backup file is of type VHD.
• The backup file on the backup device will always appear to have the last full backup even though only the changed blocks were transferred from your backup source.

Limitations with Windows Server Backup:

• Lack of hardware support to a variety of hardware destinations
  • No facility to perform automated backups to rdx and REV drives using the Microsoft wizards.
  • No facility to perform automated backups to NAS using the Microsoft wizards.
• Backup Monitoring and Reporting
  • Media rotation strategies are not available.
  • No notifications such as email backup status reports.
  • Impossible to automatically to see what versions of backups are available on the backup device.
  • Drive letter is removed from backup devices.
  • No facility to monitor large number of servers through centralized monitoring.
• Backup selection limitations
  • Impossible to select individual files and folders. Only entire volumes can be backed up.
  • Only local volumes can be selected and network shares are not able to be backed up.

These limitations may be resolved by using 3rd party backup software. Based on price and performance, BackupAssist is an excellent choice for system administrators to perform backups of Windows Server 2008. BackupAssist works in conjunction with the Windows Server backup engine to provide a comprehensive backup utility which extends the range of hardware destinations to which Server 2008 backups can be performed to and allows for backups of network shares. BackupAssist also offers backup monitoring and reporting functionality so that system administrators can be aware of the status of their backups.

Share this article:   Bookmark this on Delicious