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Vmware accelerator backup and BLIB Vmware backup

Level 3

Hi Team,


I have a query, If we are doing netbackup BLIB Vmware backup, is there any benefit to use netbackup VMware accelerator backup.  

Also if we doing VM accelator backup , how can we check actual size of incremental data backuped using opscenter reports on monthly basis, as Kilobytes backed will show the complete size of VM in both incremental and full. For reporting purposes we need to be sure how much actual changes we are backing in incrementals.






Level 4

Hi, I am investigating into using NBU Accelerator as well and had the same question.  Did you ever receive a response or determine an answer to your question?  Thank you in advance.

Partner    VIP    Accredited

Hi @Sachin507  @new2nbu 

Hi everyone,

Sometime ago I was talking with veritas consultant about this question because I had the same doubt. At that time I was using about netbackup 8.0 / appliance 3.0. He told me that there is not much difference between Incremental (with BLIB) and Full with accelerator enabled.

In my scenario we had a vsphere 6.0 and in this version there was a problem when CBT was enabled together with Incremental backups, as you can see below

To summarize he recommended the use of the accelarator with Full backups.

Hope this helps.


Thank you, Thiago for the reply.  This is for sure helpful.  In our environment, we did not use Incremental schedules with our VMWare Full Backups and still ran into issues with CBT in VMWare v6 as well - where the snap should not consolidate and subsequent backups would fail.   As a result, I have since disabled BLIB and was doing Full VMWare snapshots (full mapped vm for file/folder recovery).  But I want to take better advantage of the VMWare backup technology however based on what I read BLIB and Accelerator seemed to be very similarly leveraging VMWare CBT.   With Accelerator - do you have a periodic full happening b/c essentially it's a synthetic full right?  From the documentation, it seems good to periodically reset the archive bit (same as you would if there's a power outage, etc) and have a standard Full backup written.  Also from the documentation, Accelerator is not supposed to grow the catalog unnecessarily large - have you found any penalties or downsides with Accelerator.  Thanks in advance.

Level 6


I wrote a breakdown of all the confusing combinations of Accelerator + BLIB/CBT in an old post.

Here is an even older post where I explain the same thing but in a different way, like what happens if you want Accelerator but don't want BLIB, etc.

Hope these help you too.

Partner    VIP    Accredited

Hi @new2nbu ,

From what I remember no. Sometimes some virtual machines loss the "Accelarator Optimization" and "Deduplication Rate" because were migrate to another ESX or experience a high rate of change, but in my case was not frequency.

I was reading these articles below I will send below some articles to show you more about it:

VMware Incremental backups with Accelerator enabled are shown as having the same size as full backups

About the NetBackup Accelerator for virtual machines

Accelerator: full vs. incremental schedules

How the NetBackup Accelerator works with virtual machines

Accelerator notes and requirements for virtual machines

Accelerator forced rescan for virtual machines (schedule attribute)


Yes!  These articles are great and much easier to digest the differences between the technologies.  Thank you so much for linking them!

Hi Thiago,

Thank you so much for sharing.  I'm reading through each one!  Thanks again and all the best.