- ----Original Message-----
From: veritas-bu-bounces at mailman.eng.auburn.edu
[mailto:veritas-bu-bounces at mailman.eng.auburn.edu] On Behalf Of Clooney,
David
Sent: October 16, 2006 6:08 AM
To: Brenton Carbins
Cc: veritas-bu at mailman.eng.auburn.edu
Subject: Re: [Veritas-bu] 9940B

I have performed some tests after analysing bpbkar and bptm logs all all
media servers and a number of their bptm logs indicate that they are not
waiting for empty buffers, in turn telling me that an increase of the
buffer size and number should have a positive impact . 
 
Assuming you were getting "waiting for empty buffer" previously, then
you increased the number of buffers and you are no longer getting the
messages, then yes, increasing the number of buffers DID have a positive
impact.
 
If you are NOT currently getting "waiting for empty" messages, then
increase the buffer count will do nothing but consume more shared
memory.
 
If you are not getting any waiting for full, or waiting for empty buffer
messages, then there is no reason to change anything, unless you would
like to "decrease" the buffer numbers to gain more available memory
outside of the buffers.
 
  After testing our throughput has jumped around from around 11mb/sec to
40+ mb/sec which is fantastic, my concern is for the latter part of your
mail regarding tapes which have been written with a different  
 
 SIZE_DATA_BUFFERS.  
 
 When testing I took backups before and after the SIZE_DATA_BUFFERS
implementation. I then proceeded to test restores from both images
written with different Buffer sizes. 
 
 All where successful however could you shed a little more light on this
as we obviously have all our backed up data written in the current
SIZE_DATA_BUFFER and it would be a shame not to achieve the throughput
we saw when testing. 
 
What Brenton is referring to, isn't so much a performance issue as a
function issue....if you change the values you're using for
SIZE_DATA_BUFFER, you will want to thoroughly test restores from backups
written at a different number to ensure functionality.
 
Paul
====================================================================================

La version fran?aise suit le texte anglais.

------------------------------------------------------------------------------------

This email may contain privileged and/or confidential information, and the Bank 
of
Canada does not waive any related rights. Any distribution, use, or copying of 
this
email or the information it contains by other than the intended recipient is
unauthorized. If you received this email in error please delete it immediately 
from
your system and notify the sender promptly by email that you have done so. 

------------------------------------------------------------------------------------

Le pr?sent courriel peut contenir de l'information privil?gi?e ou 
confidentielle.
La Banque du Canada ne renonce pas aux droits qui s'y rapportent. Toute 
diffusion,
utilisation ou copie de ce courriel ou des renseignements qu'il contient par une
personne autre que le ou les destinataires d?sign?s est interdite. Si vous 
recevez
ce courriel par erreur, veuillez le supprimer imm?diatement et envoyer sans 
d?lai ?
l'exp?diteur un message ?lectronique pour l'aviser que vous avez ?limin? de 
votre
ordinateur toute copie du courriel re?u.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: 
http://mailman.eng.auburn.edu/pipermail/veritas-bu/attachments/20061016/e2fd0eaa/attachment.html