Netbackup retries causing huge number of delta files on VM when Snapshot fails at backup

[Tom-B_]

Netbackup retries is causing a huge number of delta files to accumulate on the virtual guest when the backup quiesced snapshot fails at backup time.

How can we limit the number of retries?  Is it possible to get Netbackup to recognize the type of failure that is occuring and have it operate a specific way, based on the status code?  

We are getting the 156 status code and Netbackup seems to keep on trying a number of times.  Part of this may be our systems admins re-attempting the failed backup without ever resolving the underlying problem, but, I beleive Netbackup is attempting 20 times during each event.  In no time at all, we find the guest has accumulated 60 or more delta files.  An optimal solution would be for Netbackup to suspend the backup job and notify the backup admin whenever it encounters the 156 status code, after maybe 5 attempts.  Perhaps even have the retry occur at greater intervals.  

Thanks,

Tom

[Marianne]

Please let us know all relevant info:

NBU version (and patch level) on master and backup host
OS on master and backup host

Number of tries in Host Properties -> Master server -> Global Attributes.

Please also let us know how this issue is related to Symantec NetBackup Appliances?

[Tom-B_]

Version: 7.5.0.2

OS on Master: Linux, preinstalled on the NetBackup Appliance

OS on Backup Client: Windows Server 2003

Number of retries: 2 every 12 hours.

Our admin has explained to me that NBU is not actually doing the snapshots, but that it is asking VMware to do them.  I guess the question becomes, why is VMware re-attempting the failed snapshots so many times and how can we limit that.

[Nicolai]

Netbackup only retry 5 times but the API may very well trigger a lot more snaps

Take a look at this blog: https://www-secure.symantec.com/connect/blogs/nuts-and-bolts-netbackup-vmware-handling-orphaned-snap...

[Tom-B_]

Upon further investigation, there is a URL that details the "VMware - Advanced Attributes dialog" for NetBackup Enterprise Server 7.0 7.6.  In a table where it lists configuration parameters, it says:

Snapshot retry count

Sets the number of times the snapshot is retried. The default is 10. The range is 0 to 100. This option and the snapshot timeout and snapshot creation interval provide flexibility in the creation of snapshots. For most environments, the default values are usually best. In special circumstances, it may be helpful to adjust these settings. Example considerations are the size of the virtual machine and the processing load on the VMware server.

I have been unsuccessful at finding a similar document for Version 7.5.  Our admininstrator has been unable to locate where this setting may be modified.

[Marianne]

Always good to mention URL when you copy & paste from it - just to ensure we are all on 'the same page'...

http://www.symantec.com/docs/HOWTO70998

Seems these options will only be available as from NBU 7.6.

Advanced options available in 7.5 can be found in NBU for VMware Admin Guide on p.57 - 59  :

VMware - Advanced Attributes dialog

This dialog appears when you click Advanced on the VMware policy tab.

[Tom-B_]

Thanks for the reply.  I actually hyperlinked the URL, which is not the most obvious thing to do, in order to provide reference.  As I look at it now, it is clearly difficult to see that it is a link. 

The URL that I provided has a very clear grid of options where one can readily find the aforementioned parameter, "Snapshot Retry Count."  In the link you suggested, I am not having any success in locating this parameter.  Does the parameter still exist in some form?  If so, how does one navigate to it?

Appreciate any help you may be able to provide on this.

[Marianne]

Have you seen the following in my post above?

http://www.symantec.com/docs/HOWTO70998

Seems these options will only be available as from NBU 7.6.

If you click on 'Show all' under Product(s), you will see :
NetBackup Enterprise Server
7.6
 

Advanced options available in 7.5 can be found in NBU for VMware Admin Guide on p.57 - 59  :

VMware - Advanced Attributes dialog

This dialog appears when you click Advanced on the VMware policy tab.

[Tom-B_]

I have seen your post, but I think that, owing to the fact that I used a hyperlink in the post where I mentioned the setting, perhaps you have not seen what I was looking at.  The HOWTO was referencing 7.0 and 7.6.  (It is odd that when clicking the products link you suggested, it only shows 7.6.)

http://www.symantec.com/business/support/index?page=content&pmv=print&impressions=&viewlocale=&id=HO...

I find it strange to imagine that the product development team would remove this setting from the intervening release.  Are you, in fact, telling me that the setting is not available in 7.5 or am I misunderstanding you?  I don't see, in your posts, a clear indication one way or the other.  Since I am looking for the information to relay to a colleague, who has hands-on access to the program, my options are limited to communicating your response and any relevant documentation.

I am sure all of this back and forth could have been avoided, had I included the actual URL, as opposed to the hyperlink.  Sorry about the confusion.

[Marianne]

I can see all of those options in our 7.6 FA installation in our lab.

These options were not present in NBU 7.5 or in any prior version.

The available options in 7.5 are listed in the manual as per my previous post.

Here is the link to NBU 7.6 manual: NetBackup for VMware Administrator's Guide