Netbackup LTO 5 ⁠⁠⁠SIZE_DATA_BUFFERS and NUMBER_DATA_BUFFERS Value

[Five5]

Hi support,

I would like to know the value for SIZE_DATA_BUFFERS and NUMBER_DATA_BUFFERS on Netbackup v7.0.1 for lto5. I found this post https://vox.veritas.com/t5/NetBackup/Netbackup-7-1-slow-backup-speed/td-p/429865 , however it only mention on lto 4.

[TraceyBunyard]

Hi,

I'm not going to be able to help here, I'm afraid. Can you repost your question into the NetBackup space and I'm sure it will get answered. https://vox.veritas.com/t5/NetBackup/bd-p/netbackup

If you ever have a NetBackup Self Service question, come back to me :) 

https://vox.veritas.com/t5/NetBackup-Self-Service/Downloading-a-trial-copy-of-NSS-NetBackup-Self-Ser...

Thanks,

Tracey

[Marianne]

@Five5
I have moved your post to the NetBackup forum.

The settings mentioned in the 2011 post that you found is good for any modern tape. You will also notice that Nicolai has mentioned the Planning and Performance Tuning Guide. This guide will explain how to read bptm log to see the effects of buffer adjustments on your media server(s).

PS:
Are you aware that your version of NBU is no longer supported?

[Genericus]

You should know that the number and size of the buffers won't matter if you cannot generate and transmit the data at speed.

So firstly you should ensure you can generate the data, and it can get to the tapes.

Having said that, LTO5 caps at 256K buffer size, writing to disk you can go larger.

Number of buffers is a function of the system - cpu and memory. You can experiement writing the same image using different values to see your optimal setting - I know too many / too large buffers can actually perform WORSE in some cases.

Since NetBackup gives you computed data, the effects of compression will artificially change some numbers you see. I personally have written to an LTO5 tape faster than the rated max speed, due to this compression, then the next image writes at less than 100MB/Second...