Video Screencast Help

Throughput is very low for the new drives

Created: 15 Nov 2013 | 7 comments
skrp's picture

Hi All,

We have bought two LTO6 Drives for HP TL4000 Library. We are having a very low throughput for backups with these drives like not more than 30MB/sec which we should actually get like around 150-160MB/sec.

Our OS is Windows 2007 SP2

We are using netbackup 7.1 for the backups.

Can someone help me to improve my drives performance. Do I need to make any configuration changes.

We are using a cleaning media which we used earlier when we had LTO4 drives. Its ID shows as CLNU00L1. Can we use this for LTO6 Drives. This may sound silly but i'm very new to this. Please help me out.

Operating Systems:
Discussion Filed Under:

Comments 7 CommentsJump to latest comment

Nicolai's picture

Sound like you are missing tuning of NUMBER_DATA_BUFFERS & SIZE_DATA_BUFFERS

Take a look in the netbackup performance & tuning guide page 123 for advice and configuration:

I recommend settings:




Happy tuning.

Best Regards


Assumption is the mother of all mess ups.

If this post answered your'e qustion -  Please mark as a soloution.

huanglao2002's picture

1 Please Check the HCL

2 download the new netbackup device mapping file,and load.

3 upgrade the windows tape driver and upgrade drive firwall.

4 reference Nicolai' advice do a performance test.

quebek's picture

Is your new LTO6 drive a real bottle neck?? 150 - 160 MB/s is twice as much as the 1 Gbps ethernet bandwith (the 80% of 1 Gbps of it, to be frank, which I am using to asses network throughput). Can your clients push more then these 30 MB/s to your media server???

Marianne's picture

Our OS is Windows 2007 SP2

Really? Probably not...............?

In order to performance tune, you need to determine transfer rate of each component in the data path.

Firstly, determine read speed of client disk. Use bpbkar test. 
See and

Next test is to determine network transfer rate between client and media server - use OS tools such as ftp or network copy. What are the results?

Supporting Storage Foundation and VCS on Unix and Windows as well as NetBackup on Unix and Windows
Handy NBU Links

muhanad.daher's picture

Are you tried to update library driver?  if throughput on all client same, may the problem on drivers.  check the ftp network copy as Marriane suggested before.


Muhanad Daher

Senior Data Center Engineer

skrp's picture

Hello All,

Firstly apologies for the delay to respond and thanks for all the suggestions on the post. I will check all these and get back with the results ASAP.

skrp's picture

Hi All,

Thank you very much for the responsed. Problem was with the drives, we have replaced them and everything seems to be working fine now. Thanks again.