The filer will send quite a lot of traffic back to the server with the 
NDMP option installed.  You want good IP connectivity and spare CPU power 
on the 'Netbackup for NDMP' server.  There may be a few options on the 
filer, but I don't recall any way to set the buffer size.    NDMP 
appliances tend to be hard-coded at 64K, as that works with all tape 
drives, but obviously cannot make LTO reach top speed.

In fact I found this in the man pages of a filer:

DATA_BLOCK_SIZE     4-64    63  Specifies the tape blocking factor in 
kilobytes.
 
These are NDMP protocol options, in principle you can put them in the file 
list and they are passed to the NetApp.   But wow, you can reduce the 
block size..but the default is 63 blocks.  That is Data OnTap 6.5, I guess 
it might have changed in 7.  Not good!

William D L Brown




"Paul Keating" <pkeating AT bank-banque-canada DOT ca> 
Sent by: veritas-bu-admin AT mailman.eng.auburn DOT edu
17-Oct-2005 13:46
 
To
"Veritas List" <veritas-bu AT mailman.eng.auburn DOT edu>
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Subject
[Veritas-bu] NDMP performance and tuning






I'm currently doing some NDMP testing.
 
Netbackup 5.0MP4 master server, on Sun V240/Solaris 8
NetApp gf940 filer, SAN attached to Hitachi storage.
Adic Scalar 24 library with two IBM LTO2 SCSI drives and onboard FC 
bridge.
 
all devices are attached via a Brocade SW24k.
 
"Virtual Private SAN" utility on the Library FC brdige was used configured 
to advertise the robotic controller and one drive to the master server, 
and the other drive to the filer.
 
Brocade has once zone for filer and drive, and second zone the master 
server, library and 2nd drive.
 
NDMP backups have been running at 14,000, 16,000, 18,000 kbps........not 
in the 30,000+ neighbourhood I was expecting.
 
Seems buffers and such on the master server would have *zero* effect on 
NDMP data rates.....filer options for NDMP are basically just "on" and 
"off".
 
is there any IP "heartbeat" between filer and master that coul/would 
affect data throughput?
 
Paul