Exchange Server backup

Question

Hello!

Suppose you've been tasked to configure Exchange Server backups in Windows Server Backup with the following schedule:

1. Sunday - Full
2. Monday through Friday - Incremental or Differential

Maybe I'm missing something but I don't see how I can create two separate schedules in Windows Server Backup - there's only the Optimize Backup Performance window in which I can choose the backup option: either Full Backup or Incremental Backup - and no "Differential" option in there.:

Q1: How can I create two separate schedules (for Full and Incremental backups) in WSB?

Q2: Am I getting it right that WSB does not support differential backups?

P.S. Frankly speaking I don't understand what does the Incremental backup option do in the aforementioned screenshot - by default WSB always makes (at least tries) to create incremental backups even when the Backup Option is set to Full backup:

Here I've taken two full volume backups in a raw and used space after the second backup became 53.9 GB while it was 53.8 GB after the first backup.

Used space on volume C: (the one that was backed up):

Regards,

Answer 1

Hi Hram Admin

Thank you for posting your question in the Microsoft Q&A forum regarding Windows Server Backup (WSB) schedules and Exchange Server behavior. This is a common point of confusion because WSB handles data storage differently from how it handles application consistency (Exchange logs).

Based on your specific questions and the explanation of the behavior shown in your screenshots, I would like to share some information and recommendations that I hope will help.

Create two separate schedules (for Full and Incremental) in WSB?

You cannot create two separate schedules (ex: Sunday Full, Weekdays Incremental) using the Windows Server Backup GUI. The GUI allows only a single backup policy per server.

To achieve a complex schedule, you must use Windows Task Scheduler combined with the wbadmin command-line tool. You would disable the automatic schedule in the WSB GUI and create two Task Scheduler jobs: (wbadmin start backup | Microsoft Learn)

• Sunday Task (Full):

    wbadmin start backup -backupTarget:D: -include:C: -vssFull -quiet 
  

  (The -vssFull switch tells Exchange to truncate transaction logs after a successful backup).
• Weekday Task (Incremental):

    wbadmin start backup -backupTarget:D: -include:C: -delivery:incremental -quiet
  

For more information, you can referral to:

Use Windows Server Backup to back up Exchange | Microsoft Learn

Using Windows Server Backup to back up and restore Exchange data | Microsoft Learn

Does WSB support Differential backups?

No, Windows Server Backup does not natively support Differential backups. It supports only Full and Incremental.

Regarding your P.S. and screenshots (The "53.8 GB vs 53.9 GB" observation), you noticed that running a second "Full Backup" did not double the used disk space. This is actually expected behavior and is a feature of WSB. It is important to distinguish between Application Backup Type and Storage Backup Type:

• VSS Backup: When you select "VSS Full Back up," WSB signals Exchange to verify the database and truncate (delete) the transaction logs.
• Disk Storage: When backing up to a local disk, WSB behaves like an incremental backup at the block level, even if "Full" is selected. WSB performs block-level comparison between the source volume and the existing backup, writing only the modified blocks to the target disk. It leverages Volume Shadow Copy snapshots so that each backup is presented as a full backup during restoration, while in practice consuming only the storage footprint of an incremental backup.

Your second backup was indeed a "Full VSS Backup" (logs were truncated), but because very little data changed on the disk between the two runs, WSB only wrote the changed bits (~0.1 GB), saving you significant storage space.

Because WSB is efficient at the block level, most Exchange administrators do not need to set up complex schedules via Task Scheduler. I recommend simply configuring a Daily Schedule in the WSB GUI with the "Faster Backup Performance" option enabled. This ensures Exchange logs are truncated daily (VSS Full) and storage space is optimized (Block-level Incremental).

Hope this information helps.

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Answer 2

Hi Hani-NG,

Thank you so much for your explanation!!! In fact this -

"For more information, you can referral to:

Use Windows Server Backup to back up Exchange | Microsoft Learn

Using Windows Server Backup to back up and restore Exchange data | Microsoft Learn "

...is not true: I've already read those articles and they didn't have the information you posted here :)

I'd like to clarify a few more points here, please:

1. "This is actually expected behavior and is a feature of WSB. It is important to distinguish between Application Backup Type and Storage Backup Type:
   • VSS Backup: When you select "VSS Full Back up," WSB signals Exchange to verify the database and truncate (delete) the transaction logs.
   • Disk Storage: When backing up to a local disk, WSB behaves like an incremental backup at the block level, even if "Full" is selected. WSB performs block-level comparison between the source volume and the existing backup, writing only the modified blocks to the target disk. It leverages Volume Shadow Copy snapshots so that each backup is presented as a full backup during restoration, while in practice consuming only the storage footprint of an incremental backup."

I don't understand what in WSB let me choose between Application Backup Type and Storage Backup Type: if - according to the text above - Application Backup Type = VSS Backup and Storage Backup Type = Disk Storage then selecting VSS Full Back up may apply for both options if the destination is set to local volume...

In other words if

a) I select VSS Full Backup to local volume is it Application or Storage backup type?

b) I select VSS Full Backup to network volume is it Application or Storage backup type?

.2. You recommend creating a single schedule with "Faster Backup Performance" option to make sure

a) Exchange logs are truncated daily
b) storage space is optimized

...but exactly the same results may be achived by using the VSS Full Backups WITHOUT "Faster Backup Performance" option (as we discussed above) - what's the difference in this case???

(this article in 8. offers to create VSS Full backups without that option).

Regards,

Answer 3

Hani-Ng, I've learnt many MS official curriculums on various Windows Server editions (which contained chapters on Windows Server Backup) and read plenty of articles online but have NEVER seen anything so useful as your posts - thank you so much for your explanations!

Regards,

Answer 4

P.S.

MS' explanation of incremental backups seems rather weird:

If Incremental backups may "reduce disk throughput..." then why it is NOT recommended for servers with disk-intencive operations??? Shouldn't the servers with high disk loads aim not to add extra load caused by WSB???

Answer 5

Hani-Ng, thank you so much for your clarification!!!

Once again: MS documentation may explain dozens of times how to run a backup job and never explain how it is works under the hood!

Regards,