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[Veritas-bu] Storage Tek Drives
2002-05-24 09:10:45
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Hi David,
No 9840 haven't a 64Kb internal buffer.
The maximum buffer size you can put is 256K.
I work all the time with 9840 on mixed environment and I've never
encountered your problems.
You have to check microcode level (very very important).
And in a (very) good environment you can have more than 35Mb/s on a 9840.
Fabrice
-----Original Message-----
From: Spearman, David [mailto:spe08 AT co.henrico.va DOT us]
Sent: vendredi 24 mai 2002 12:56
To: 'David A. Chapa'; Veritas NBU_Q&A
Subject: RE: [Veritas-bu] Storage Tek Drives
We have 9840A drives on site. The 9840a has a 64kb internal buffer. It has
been our experience that any thing over 64kb buffers set in nbu will cause
error 14's (at a minimum). Best bet with the A's is to back off buffer size
(also receive buffer) to 64kb. If you get waiting for buffers this is one of
those cases where you will want to increase num_buffers. However, the 9840a
while a good tape unit has never shown the kind of throughput as advertised,
especially in a mixed invironment of MS / Unix old / new machines. I have
not had a chance to check out the B variant. The installation manual should
include specs on the internal buffer. If you find a way to make their system
scream let me know.
David Spearman
County of Henrico, Va.
-----Original Message-----
From: David A. Chapa [mailto:david AT datastaff DOT com]
Sent: Thursday, May 23, 2002 5:16 PM
To: Veritas NBU_Q&A
Subject: [Veritas-bu] Storage Tek Drives
The drives: 9840a's and b's
A client installed a new media server, ran some test backups and was
disappointed with the results. We looked at how it was configured and I
mentioned that he may want to increase the buffer size to 256K. They did,
but now can't restore the data from the previous backups that were done at
the default block size.
I am almost positive I have had customers tweak this value up and down
without sacraficing their abilities to do restores (DLT mostly).
Is this typical of the 9840 drives?
If so, my alternative plan is going to be to
1. duplicate the images from the new media server to the master server.
2. bpexpdate images on the new server
3. duplicate these images on the master to meet their DR level.
is there a better idea?
David
<><><><><><><><><><><><><><><><><><><><>
David A. Chapa
NetBackup Consultant
DataStaff, Inc.
http://www.datastaff.com
847 413 1144
---------------------------------------
http://www.NetBackupcentral.com
_______________________________________________
Veritas-bu maillist - Veritas-bu AT mailman.eng.auburn DOT edu
http://mailman.eng.auburn.edu/mailman/listinfo/veritas-bu
_______________________________________________
Veritas-bu maillist - Veritas-bu AT mailman.eng.auburn DOT edu
http://mailman.eng.auburn.edu/mailman/listinfo/veritas-bu
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<P>
<FONT SIZE=2>Hi David,</FONT>
</P>
<P><FONT SIZE=2>No 9840 haven't a 64Kb internal buffer.</FONT>
</P>
<P><FONT SIZE=2>The maximum buffer size you can put is 256K.</FONT>
</P>
<P><FONT SIZE=2>I work all the time with 9840 on mixed environment and I've
never encountered your problems.</FONT>
</P>
<P><FONT SIZE=2>You have to check microcode level (very very important).</FONT>
</P>
<P><FONT SIZE=2>And in a (very) good environment you can have more than 35Mb/s
on a 9840.</FONT>
</P>
<P><FONT SIZE=2>Fabrice</FONT>
</P>
<P><FONT SIZE=2>-----Original Message-----</FONT>
<BR><FONT SIZE=2>From: Spearman, David [<A HREF="mailto:spe08 AT co.henrico.va
DOT us">mailto:spe08 AT co.henrico.va DOT us</A>]</FONT>
<BR><FONT SIZE=2>Sent: vendredi 24 mai 2002 12:56</FONT>
<BR><FONT SIZE=2>To: 'David A. Chapa'; Veritas NBU_Q&A</FONT>
<BR><FONT SIZE=2>Subject: RE: [Veritas-bu] Storage Tek Drives</FONT>
</P>
<BR>
<P><FONT SIZE=2>We have 9840A drives on site. The 9840a has a 64kb internal
buffer. It has</FONT>
<BR><FONT SIZE=2>been our experience that any thing over 64kb buffers set in
nbu will cause</FONT>
<BR><FONT SIZE=2>error 14's (at a minimum). Best bet with the A's is to back
off buffer size</FONT>
<BR><FONT SIZE=2>(also receive buffer) to 64kb. If you get waiting for buffers
this is one of</FONT>
<BR><FONT SIZE=2>those cases where you will want to increase num_buffers.
However, the 9840a</FONT>
<BR><FONT SIZE=2>while a good tape unit has never shown the kind of throughput
as advertised,</FONT>
<BR><FONT SIZE=2>especially in a mixed invironment of MS / Unix old / new
machines. I have</FONT>
<BR><FONT SIZE=2>not had a chance to check out the B variant. The installation
manual should</FONT>
<BR><FONT SIZE=2>include specs on the internal buffer. If you find a way to
make their system</FONT>
<BR><FONT SIZE=2>scream let me know.</FONT>
</P>
<P><FONT SIZE=2>David Spearman</FONT>
<BR><FONT SIZE=2>County of Henrico, Va. </FONT>
</P>
<P><FONT SIZE=2>-----Original Message-----</FONT>
<BR><FONT SIZE=2>From: David A. Chapa [<A HREF="mailto:david AT datastaff DOT
com">mailto:david AT datastaff DOT com</A>]</FONT>
<BR><FONT SIZE=2>Sent: Thursday, May 23, 2002 5:16 PM</FONT>
<BR><FONT SIZE=2>To: Veritas NBU_Q&A</FONT>
<BR><FONT SIZE=2>Subject: [Veritas-bu] Storage Tek Drives</FONT>
</P>
<BR>
<P><FONT SIZE=2>The drives: 9840a's and b's</FONT>
</P>
<P><FONT SIZE=2>A client installed a new media server, ran some test backups
and was</FONT>
<BR><FONT SIZE=2>disappointed with the results. We looked at how it was
configured and I</FONT>
<BR><FONT SIZE=2>mentioned that he may want to increase the buffer size to
256K. They did,</FONT>
<BR><FONT SIZE=2>but now can't restore the data from the previous backups that
were done at</FONT>
<BR><FONT SIZE=2>the default block size.</FONT>
</P>
<P><FONT SIZE=2>I am almost positive I have had customers tweak this value up
and down</FONT>
<BR><FONT SIZE=2>without sacraficing their abilities to do restores (DLT
mostly).</FONT>
</P>
<P><FONT SIZE=2>Is this typical of the 9840 drives?</FONT>
</P>
<P><FONT SIZE=2>If so, my alternative plan is going to be to</FONT>
</P>
<P><FONT SIZE=2>1. duplicate the images from the new media server to the master
server.</FONT>
<BR><FONT SIZE=2>2. bpexpdate images on the new server</FONT>
<BR><FONT SIZE=2>3. duplicate these images on the master to meet their DR
level.</FONT>
</P>
<P><FONT SIZE=2>is there a better idea?</FONT>
</P>
<P><FONT SIZE=2>David</FONT>
</P>
<P><FONT
SIZE=2><><><><><><><><><><><><><><><><><><><><></FONT>
<BR><FONT SIZE=2>David A. Chapa</FONT>
<BR><FONT SIZE=2>NetBackup Consultant</FONT>
<BR><FONT SIZE=2>DataStaff, Inc.</FONT>
<BR><FONT SIZE=2><A HREF="http://www.datastaff.com";
TARGET="_blank">http://www.datastaff.com</A></FONT>
<BR><FONT SIZE=2>847 413 1144</FONT>
<BR><FONT SIZE=2>---------------------------------------</FONT>
<BR><FONT SIZE=2><A HREF="http://www.NetBackupcentral.com";
TARGET="_blank">http://www.NetBackupcentral.com</A></FONT>
</P>
<P><FONT SIZE=2>_______________________________________________</FONT>
<BR><FONT SIZE=2>Veritas-bu maillist - Veritas-bu AT
mailman.eng.auburn DOT edu</FONT>
<BR><FONT SIZE=2><A
HREF="http://mailman.eng.auburn.edu/mailman/listinfo/veritas-bu";
TARGET="_blank">http://mailman.eng.auburn.edu/mailman/listinfo/veritas-bu</A></FONT>
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<P><FONT SIZE=2>_______________________________________________</FONT>
<BR><FONT SIZE=2>Veritas-bu maillist - Veritas-bu AT
mailman.eng.auburn DOT edu</FONT>
<BR><FONT SIZE=2><A
HREF="http://mailman.eng.auburn.edu/mailman/listinfo/veritas-bu";
TARGET="_blank">http://mailman.eng.auburn.edu/mailman/listinfo/veritas-bu</A></FONT>
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