Forum Discussion

darran02's avatar
darran02
Level 2
10 years ago

Backup Exec 15 backing up full vhdx, even though it's not full.

Hello!

I have recently installed Backup Exec 15 and started to backup all my servers. They are all virtual machines running on Hyper-V. I noticed that the byte count on some backup jobs show that the whole virtual disk is backed up, even though the drive isn't full. All our disk are dynamically expanding virtual hard disks (vhdx). An example:

  • Byte Count: 1.99 TB
  • Elapsed Time: 1:10:00:53
  • Maximum Disk Size: 1.99 TB
  • Used space on disk according to VM: 110 GB
  • Actual size of vhdx file: 241,5 GB

I have another example where the values are about the same, but only 512 GB is allocated on the virtual disk. Can Backup Exec back up unallocated space? Is there a reason as to why the whole disk is backed up? Where does the extra data come from? Why is it taking so long to run these jobs? Any help or tips are appreciated!

15
Agent for Microsoft Hyper-V
Backing Up
Backup and Recovery
Backup Exec
Deduplication Option
Performance
Tip-How to
Virtualization
Windows Server (2003-2008)
  • VJware's avatar
    VJware
    10 years ago

    BE will backup only the "used blocks" of the vhd / vhdx and not the empty space. This is called as Disk Optimization in BE terms. Have a look @ this KB article for certain scenarios where this will not work - https://support.symantec.com/en_US/article.HOWTO99704.html

    Secondly, instead of the job log, have a look @ the actual storage itself to verify what actual size was backed up.

     

     

  • CraigV's avatar
    CraigV
    Moderator
    10 years ago

    Hi,

     

    Backup Exec will backup the fully-sized disk, including the white space.

    Thanks!

  • darran02's avatar
    darran02
    Level 2
    10 years ago

    Is there a way to not back up the whole disk? Most other jobs only back up about 30 GB even though the disks have a maximum size much larger.

  • CraigV's avatar
    CraigV
    Moderator
    10 years ago

    You'd have to do this via Remote Agent and only backup the files, which negates what you're trying to do with your backups if you're using the Hyper-V agent.

  • darran02's avatar
    darran02
    Level 2
    10 years ago

    I see. But why does most VMs not backup the full disk? For example, I have another VM (with agent for Windows insalled, as all other VMs), where Backup Exec backs up 36.5 GB, but the virtual disk has a maximum size of 512 GB, and a physical size of 85.72 GB. Why doesn't that job take 512 GB?

  • VJware's avatar
    VJware
    Level 6
    10 years ago

    BE will backup only the "used blocks" of the vhd / vhdx and not the empty space. This is called as Disk Optimization in BE terms. Have a look @ this KB article for certain scenarios where this will not work - https://support.symantec.com/en_US/article.HOWTO99704.html

    Secondly, instead of the job log, have a look @ the actual storage itself to verify what actual size was backed up.