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Backup Exec 2014 and Hyper-V Incremental Backups - Always Full Backups?

tl;dr summary:  Is there any way of configuring Backup Exec 2014 to perform incremental backups of Hyper-V guest operating systems that doesn't result in a full backup of the guest VM being created each time an incremental backup is run?


I'm looking for some clarification / better understanding of using Backup Exec 2014 to perform incremental backups of Hyper-V virtual machines.

I am running a Backup Exec 2014 Media Server on a Windows Server 2012 R2 host.  This media server backs up a couple of separate virtualization host servers in our environment.  The virtulization host servers are running Windows Server 2012 R2, and each host server hosts several Windows-based (2003 through 2012 R2) guest operating systems.  The Backup Exec Agent for Windows is installed on the virtualization host servers, as well as the various guest operating systems.

I would like to perform a full backup of the Hyper-V guest operating systems once a week, and a differential or incremental backup of the guest operating systems every other day of the week.  However, it appears that every backup of the guest OSes, whether full or incremental, results in a full backup being performed (at least judging from the amount of disk space the backups are consuming.)

I have reviewed the following Symantec support URLs,


which pertain to earlier versions of Backup Exec and Windows Server, and basically state that differential or incremental backups of Hyper-V guests is not possible, because Microsoft doesn't provide any API to perform such backups of Hyper-V guest OSes.

However, the Backup Exec 2014 Agent for Hyper-V documentation states "This version of Backup Exec supports the Windows Server 2012 vhdx file format and Microsoft incremental backups" (p. 884) and also describes differences between Backup Exec incremental backups for Hyper-V and Microsoft incremental backups for Hyper-V.

So, my questions are:

  • Do incremental backups of Hyper-V guests require the guest VMs to be using .VHDX format for their virtual hard disks for incremental backups to work properly?
  • Is there any way of using Backup Exec to perform incremental backups of Hyper-V guest operating systems that don't result in a full backup being created each time an incremental backup is run?

What are the best practices here?  I like the idea of performing backups of the Hyper-V guests running on the host server, but with every backup essentially being a full backup, I don't have enough backup storage capacity.  I could back up each Hyper-V guest OS as a "native" server, but then I lose the ability to quickly restore a full VM; I'd have to restore as if it were a physical server.

Any guidance or clarification would be greatly appreciated.  Thanks!



9 Replies

Hello craigpower, take a look

Hello craigpower,

take a look at these TechNotes:  and

As far as I am aware BE 2014

As far as I am aware BE 2014 should be able to do a block level incremental using the Hyper-V agent or an Incremental backup using the Microsoft enabeld method. With the block level method being controlled by settings in BE and the Microsoft method configured within the operating system/powershell and not backup Exec itself.  As such you should have 2 methods to run an Incremental of a Hyper-V VM. (don't try to use both on same system)

The BE 2014 admin guide Hyper-V section does indicate an option to use the full backup method if incremental or diffierntial cannot be performed. In a back-to-front way this does imply that apart from certain configurations Incrementals confgured within Backup Exec should be possible.

Thanks, Colin, and apologies

Thanks, Colin, and apologies for the delayed response to this thread.

Unfortunately, what I'm experiencing is that even though Backup Exec 2014 Agent for Hyper-V indicates that it's supposed to be able to perform incremental backups of Hyper-V guests, that's not what I'm actually experiencing "in the real world."  I'm using only the Backup Exec method; I haven't configured the Microsoft method, and don't plan to.

I have seen the setting you mentioned, "Use the full backup method for virtual machines that do not support incremental or differential backups", and that setting is currently on (checkbox is marked) for the backups that I have configured.  I will turn this setting off for the VM host systems to see what the results are then.

Curious, and a bit disappointing.  I would really like to manage backups exclusively through the VM host systems, but it's not behaving as I'd hoped it would.  I may need to revert to backing up the VM guest systems as if they were physical systems.

Any other thoughts or suggestions would be welcome!


Hi craigpower,   We have the

Hi craigpower,


We have the same problem on the BackupExec 2014.

Turned the setting-off for "Use the full backup method for virtual machines that do not support incremental or differential backups", but it returned an error. Any luck on your side?

Hi niknok - apologies for the

Hi niknok - apologies for the delay in responding.  Unfortunately, no; I made that change for VMs that use the VHDX format for their storage, but BE still seems to be performing a full backup every time a differential is scheduled.

I will also be moving on from my position with this organization soon, so I will not be able to further troubleshoot this problem.  Perhaps my successor will have better success with this issue.



Hi craigpower, how do you

Hi craigpower, how do you recognize that is a full backup? In our case we are backing up a virtual Machine (running in a Windows 2008 R2 Hyper-V Host (still a VHD Format) to a "Backup to Disk Device". It looks to me that it makes a inkremental Backup (Full Backup of the VHD about 200GB, Inkremental about 4GB). But the Problem is the time-consuming. The Full Backup takes about 90 Minutes, and the Inkremental about 70 Minutes. And that is what i do not understand. Why does it take so long when he only has to backup 4GB. And also there are now changes to the VHD (because its a Testing Envireonment). I hope you can answer me (nevertheless you are leaving the organization). Regards Rainer

Hi, I have the same


I have the same Problem.

The duration of differential Backups are insignificant faster as Full-Backups. 

It seems for me that CBT does not work.

I think that the Hyper-V.vhd is always read completly from Backup Exec Agent and than Backup Exec decide which diferential data should be transport over the network. The reading of the complete vhd requiere the bigest time.

I hope there is a soluten for this problem.


The other problem is, that all Backups need very long time. The jobrate of "fullbackups to disk" of Hyper-Vs are 2500MB/min. I tested an other backup-software on the same environment and it was by 6000MB/min. It is a 10GBit Network.


I hope there is a solution for this.



Glad this thread is still

Glad this thread is still open, as I'm having the same issue. I have 8 Windows 2012 R2 hypervisors, 3 are running BE 2014 SP1 inside Windows 2008 VMs (yes, 3 media servers), other 5 host a Windows 2008 AD domain with Exchange & SQL apps and several more virtual machines (12 total). Backing up weekly full / daily differential. Using Agent for Apps. and Agent for Virtual Machines. Backups go to disk-based storage (VHDX partitions) local to the media servers. This is a development suite for BE2014 as a replacement for BE2010. It's for a harsh environment and fault tolerance is important to us.

I am foggy on the "Microsoft Method" vs. the "Backup Exec Method". Is this virtual agent method vs. traditional file-based? I am using the first, backing up virtual machine objects through the hypervisors as detailed in the Administrator's Guide Appendix D.

I am getting familiar with the message, "A full backup was run on this virtual machine, since the option to fall back to a full backup was selected. Incremental\\differential backups are not supported for this virtual machine". Sometimes the differentials run correctly (no message in the job log, smaller backup size, lower job rate), sometimes it runs as full (message in job log, backup is the same size as the weekly full). I have not seen a pattern to when it works or not. Job rate s not an issue for me.

I just verified that the guys who set up this system used "Dynamically expanding disks" vs. fixed size or "Permanent" to save time in the build, and I am wondering if that has an effect on Change Block Tracking. Virtual disks on the guests are all (VHD). I would also be interested in anything from anyone about why a Hyper-V virtual machine would sometimes be supported for differential backup, and sometimes not!

EDIT: Read lmosla's links. I have change the BE Catalog Path from default to E:\<path> (incidentally there is a bug here and saving options fails unless you create the target folder first).

Will follow up on Colin Weaver's post about MS Incremental Backups.

I am having a similar issue.

I am having a similar issue. Although i do not get the "full backup was run" message. Differentials are running correctly. I do have an issue with the time it takes to perform the differential.


Bexec 2014 backing up a HyperV server with all VM's to dedup and immediately duplicate to tape on completion.


Full backup on friday night and diff every week day. Hyperv vhd data was around 1.5 TB before.


I have recently added an Exchange VM at 1.5TB. Now the Diff backup is correctly backing up the Exchange VM as differential, using client side dedup, as with all the other VM's ... however the agent on the hyperV runs through entire VHD structure at 100MB p/s (my SAN drive read speed.) for several hours. Same for all the other VM's (problem existed before but never bothered me as the entire server diff backup took 6 hours. Since adding the Exchange, it takes 15 hours + and we have a secondary Exchange being added soon. No time left to do tape duplication on a 24 hour cycle. . .


Diff job is set to back up block level changes on the VM. Total diff backup size for the exchange VM is correctly around 40GB (around 100GB for all the VM's) or so daily. I can live with the server taking 6 hours to back up. 20 is asking for trouble.


PS: i have a high availability hyperV cluster as well, and can move select VM's there. It does exactly the same thing when doing diff backup, so will just be moving the problem around.


I hope someone can shed some light here.