By Yuka / Last update December 13, 2021

Question: How does Windows Server Backup compression work?

I would like to have the Windows Server Backup data compressed on the file system. I try to pre-enable compression for the entire volume and set compression for the .VHD after backup, but both operation fails. How does Windows Server Backup compression actually work? Any suggestions will be appreciated.

About Windows Server Backup

Windows Server Backup (WSB) was first introduced in Windows Server 2008 as replacement for the built-in Windows NTBackup utility.

Microsoft, of course, has made some improvements that users like and some differences that users annoying. For example, you may see that a full server backup is usually smaller than data itself, because page files, temporary files, and some other files will not be included in the backup. Besides, users will complain about compression backup rate in Windows Server Backup.

Does Windows Server 2008/2012/2016/2022 Backup compress?

Though Windows has made improvements on every new edition of WSB, Windows Server 2008R2 backup compression and Windows Server 2012 backup compression are the same. By default, Windows Server Backup will not compress backed up data unless the storage devices are DVDs. Instead, it will try to compact the target backup image, like the VHD file it creates.

The mechanism of this compaction is that when you have made some changes and deletions to the source data, there will be some gaps in the subsequent backup images. By removing them, you may suddenly see your disk space getting free.

Compress backed up VHD file through DiskPart

To compact the VHD image created by Windows Server Backup, you can use DiskPart.

Please locate the .vhd file first, and press Win + R, enter "cmd" to call up Command Prompt. Then you can use the following commands in order, and press Enter after each line. 

select vdisk file="path\filename.vhd"
compact vdisk

*Please insert your own file path.

As you can see, this compression method is rather limited and you can't choose the compression ratio, so it is more recommended that you use Windows Server Backupper alternative AOMEI Backupper Server to achieve the backup compression purpose.

How to create a compressed backup with third-party tool

It is a good habit to keep more than one backup because developers. If all the backups you created are not compressed, they will likely take a lot of disk space. Therefore, you need a backup tool to perform compressed backup.

Luckily, AOMEI Backupper Server not only allows you to create backups with 3 different compression levels, but also give you more advanced features.

  • Support backing up image on multiple devices, containing CD/CD, internal hard drive, network drive, etc.

  • Support backing up the changed part with incremental backup and differential backup

  • Allows you to enable encryption for backups. This feature is very useful to private data, business data.  

  • Offer you 5 different backup schemes to delete old backup for more disk space. This feature is designed for users who need to create schedule backup regularly.

Then, refer to the steps below to create a compressed system backup.

1. Download, and run this server backup software.

Download Free-trial Server 2008/2012/2016/2019/2022/etc.

2. Click “Backup” and then choose “System Backup”. If you want to backup the entire hard drive, choose “Disk Backup” instead.

System Backup

3. In the next screen, click where the arrow points and select a destination location to receive the image backup as the source has already be included.

Select path

4. Click “Options” and “Advanced” tab, then select Normal or High compression level in the right panel. The default option is Normal.

Windows Server Backup Compression

Note: Besides compression level, there still many other useful features in AOMEI Backupper you may need.

  • It allows you to create an intelligent sector backup as well as make an exact backup. The former is recommended, because it only backup the used sectors of file systems.

  • It supports email notification, which will tell you the result of your backup.

  • It offers you many schedule settings, such as, daily backup, weekly backup, differential backup, etc.

5. Click “Start Backup” if there is no problem.

Besides, you have other settings to configure (optional).

1. Create automatic backups easily in Windows Server systems with Schedule settings. And there are 6 options you may need:

  • Daily/Weekly/Monthly: You could backup data daily, weekly, monthly for Windows Server to avoid backing up manually or forgetting to backup.

  • Event Triggers: You could trigger the backup event to perform by the following events: User logon, User logoff, System startup, System shutdown.

  • USB plug in: Once detecting the source or destination USB device of the task is plugged in, AOMEI Backupper will automatically back up the data on the USB or backup local data to USB device. It’s kind of simple and flexible.

  • Real-time Sync: If you would like to sync files to other locations as soon as they changed, please try real time file sync feature to make your files stay up to date.


Schedule Settings General

2. Configure Scheme to delete old backup images, please Enable Backup Scheme to choose a backup scheme and specify the backup numbers to maintain. 

There are 5 schemes provided for you to free up space: Full Backup Scheme, Incremental Backup Scheme, Differential Backup Scheme, Space Management Scheme, Other Backup Scheme. More details about backup scheme, please refer to the link.


With a backup in hand, you can restore to computer with the same hardware or dissimilar hardware.

Wrapping things up

As you can see, Windows Server backup compression does not support devices other than CD/DVD. So, you can only turn to trust and reliable backup tool like AOMEI Backupper Server, which fully supports compressing a backup image on different devices, including external hard drive, USB drive, network drive, etc and offer you other useful features.

However, this version only supports a few computers. If you want to protect and recover unlimited PCs, you need to use AOMEI Backupper Tech or TechPlus. It offers unlimited billable technical services to clients. It also enables you to copy installation directory for portable version creation.