[Veritas-bu] RE: Performance Tuning NBU 5.1

Hi Simon,
        I'm glad you are seeing a performance boost by moving to Fibre. It 
certainly helps in most cases. How you tune NBU will have as much to do with 
your server as with your Library/Drive Hardware.
        What kind of drives are you using? I know that AIT-3 drives run at 
12MB/sec. if you are doing a lot of image files or other uncompressible data, 
you've arrived at the best you will see for this technology.
        The obvious things I can think to check are 1) the block size you are 
using to write to tape, 2) the size of the NBU buffers on your hosts and 3) the 
number of these buffers. These three factors will greatly impact the data 
throughput to your drives.
        There is also the matter of how fast can your systems rip data off 
disk. If your disk system can only rip data at 12.5 MB/sec, then you are 
already maxed out. If you are in a *nix world, you can try dd-ing from disk to 
/dev/null to test your disk system. 
        This link will take you to a doc describing tuning parameters for LTO-2 
drives with NBU 5.0. We have our customer's use this same info for LTO-3 drives 
and for all versions of NBU.

        I hope this helps.

Mark Pinder : 
Systems Engineer: 
Spectra Logic : 

Message: 5
From: "WEAVER, Simon" <simon.weaver AT astrium.eads DOT net>
To: "'veritas-bu AT mailman.eng.auburn DOT edu'"
         <veritas-bu AT mailman.eng.auburn DOT edu>
Date: Thu, 15 Dec 2005 07:39:52 -0000
Subject: [Veritas-bu] Performance Tuning NBU 5.1


Hello
I have found a Technote on tuning NBU 4.1 however does anyone have any links
or documents on the best way to tune NBU 5.1?
 
I hqave a HP EVL going through fibre with a Master Server 5.1 and now 2
Media Servers. The Media Servers are going through fibre and on initial
tests, I am seeing approx 12500 kb/second for a stream.
 
If there are ways to try and squeeze more out of this system, then I would
like to pursue it.
 
Present backup speeds are poor, with LAN we are getting approx 1900-2500
kb/second. So quite a jump when I went onto fibre!
 
Appreciate any help or opinoins on the through put I am getting at the mo

Simon Weaver
Technical Support
Windows Domain Administrator 
EADS Astrium
Tel: 02392-708598 
Email: Simon.Weaver AT Astrium.eads DOT net