Showing results for 
Search instead for 
Did you mean: 

Netbackup to start Duplication for DSU at a certain % level

Hello Everyone,


I had encountered an issue when one of my duplication jobs were hung for a long time which caused my DSU to get filled up and finally my backup had failed. I have set the higher water mark as 98% and the lower water mark at 20%. I wanted to know if there was a way to force Netbackup to start duplicate automatically inspite of it schedule duplication frequency (which in my case is ever 6 Hrs) when the utilization reaches a certain x%.

4 Replies

Hi,   Decrease the high-water



Decrease the high-water mark value. The high-water mark value is when NBU sees the STU as being full and wont send more jobs to to it. But depending on the STU size it might then already be so close to full that it cannot except more data i.e. if its at 95% it will still accept jobs, but it might only have 5GB left, and the job might be bigger.


NBU starts cleaning and duplicating once it gets close to the high-water mark and stops this process once it reaches the low-water mark. So by setting the high to say 50% and the low to say 1% you'll clean up (duplicate) as soon as it gets to 50%, and stop at 1%


I dont know of anyway to kick it of manually aside from increasing your window, frequency.


You might consider Vault which gives you more control over this process of duplicating.




Sorry, I forgot you can

Sorry, I forgot you can select the DSU and select "Manual Relocation"


Smiley Happy


Well.. I did think about

Well.. I did think about this.. but when I read the definition of High water mark it does say that once it reaches that level it would lower the count of job being run into the DSU to prevent it from getting full.. But I did see it say that it would start duplication at the moment it reaches the high water mark.. And also I did notice once the duplication is initiated it does not bring down the level to the lower water mark.. Instead as and when new jobs come in it slowly start to expire the images on the disk.. DSU basically tries to keep as many images as possible on the disk until the need arises for it to be erased to make space for new jobs.


Frankly speaking I have not tried lowering the high water mark but wanted to get advie before I make the change.


Just pasting the note which define "High Water Mark"


The High water mark setting is a threshold that, when reached, signals to
NetBackup that the disk storage unit should be considered full. Default: 98%. As the disk storage capacity grows closer to the High water mark, NetBackup reduces the number of jobs that can write to the storage unit. NetBackup does not assign new jobs to a storage unit that is considered full. Once the capacity of the storage unit is less than the High water mark, NetBackup assigns jobs to the storage unit.
As the capacity of the unit reaches the High water mark, NetBackup reduces the
number of jobs that are allowed to write to the unit.


Yes, so you understand how it

Yes, so you understand how it works, only thing to take note of is to not lower it too far. Otherwise you'll have no images on the DSU incase you want to restore for there. Dont know if that is one of your requirements (to restore quickly from disk).