[Veritas-bu] tape drive performance on image copies

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I've found two oblique references in documents and one newsgroup posting
suggest that 256K is max for LTO.  Not exactly carved in stone but might be
good enough for testing.

-M

-----Original Message-----
From: Eric Forgette [mailto:epforgette AT overnite DOT com]
Sent: Wednesday, August 28, 2002 10:51 AM
To: veritas-bu AT mailman.eng.auburn DOT edu
Subject: Re: [Veritas-bu] tape drive performance on image copies


"Ballowe, Charles"> are you using a read host that is the same as your
write host

Yes.  perlvault allows you to set altreadhost! (and yes, the 'read host'
is the 'write host' in this case)



"Donaldson, Mark"> Check your buffer settings

"It is common to increase SIZE_DATA_BUFFERS to 256KB and
NUMBER_DATA_BUFFERS to 16.
Because the data buffer size equals the tape I/O size, the value
specified in SIZE_DATA_BUFFERS must not exceed the maximum tape I/O size
supported by the tape drive or operating system."
-http://seer.support.veritas.com/docs/183702.htm

Is this block size?  I'm digging around for the largest settings
supported by LTO.  Anyone have this?




"Donaldson, Mark">Also, consider the source images.  If they're
multiplexed...

The images I'm duplicating aren't multiplexed.

-Eric
-- 
Eric Forgette
Unix Systems Administrator
_______________________________________________
Veritas-bu maillist  -  Veritas-bu AT mailman.eng.auburn DOT edu
http://mailman.eng.auburn.edu/mailman/listinfo/veritas-bu

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<TITLE>RE: [Veritas-bu] tape drive performance on image copies</TITLE>
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<P><FONT SIZE=3D2>I've found two oblique references in documents and =
one newsgroup posting suggest that 256K is max for LTO.&nbsp; Not =
exactly carved in stone but might be good enough for =
testing.</FONT></P>

<P><FONT SIZE=3D2>-M</FONT>
</P>

<P><FONT SIZE=3D2>-----Original Message-----</FONT>
<BR><FONT SIZE=3D2>From: Eric Forgette [<A =
HREF=3D"mailto:epforgette AT overnite DOT com">mailto:epforgette AT overnite 
DOT com</=
A>]</FONT>
<BR><FONT SIZE=3D2>Sent: Wednesday, August 28, 2002 10:51 AM</FONT>
<BR><FONT SIZE=3D2>To: veritas-bu AT mailman.eng.auburn DOT edu</FONT>
<BR><FONT SIZE=3D2>Subject: Re: [Veritas-bu] tape drive performance on =
image copies</FONT>
</P>
<BR>

<P><FONT SIZE=3D2>&quot;Ballowe, Charles&quot;&gt; are you using a read =
host that is the same as your</FONT>
<BR><FONT SIZE=3D2>write host</FONT>
</P>

<P><FONT SIZE=3D2>Yes.&nbsp; perlvault allows you to set altreadhost! =
(and yes, the 'read host'</FONT>
<BR><FONT SIZE=3D2>is the 'write host' in this case)</FONT>
</P>
<BR>
<BR>

<P><FONT SIZE=3D2>&quot;Donaldson, Mark&quot;&gt; Check your buffer =
settings</FONT>
</P>

<P><FONT SIZE=3D2>&quot;It is common to increase SIZE_DATA_BUFFERS to =
256KB and</FONT>
<BR><FONT SIZE=3D2>NUMBER_DATA_BUFFERS to 16.</FONT>
<BR><FONT SIZE=3D2>Because the data buffer size equals the tape I/O =
size, the value</FONT>
<BR><FONT SIZE=3D2>specified in SIZE_DATA_BUFFERS must not exceed the =
maximum tape I/O size</FONT>
<BR><FONT SIZE=3D2>supported by the tape drive or operating =
system.&quot;</FONT>
<BR><FONT SIZE=3D2>-<A =
HREF=3D"http://seer.support.veritas.com/docs/183702.htm"; =
TARGET=3D"_blank">http://seer.support.veritas.com/docs/183702.htm</A></F=
ONT>
</P>

<P><FONT SIZE=3D2>Is this block size?&nbsp; I'm digging around for the =
largest settings</FONT>
<BR><FONT SIZE=3D2>supported by LTO.&nbsp; Anyone have this?</FONT>
</P>
<BR>
<BR>
<BR>

<P><FONT SIZE=3D2>&quot;Donaldson, Mark&quot;&gt;Also, consider the =
source images.&nbsp; If they're</FONT>
<BR><FONT SIZE=3D2>multiplexed...</FONT>
</P>

<P><FONT SIZE=3D2>The images I'm duplicating aren't multiplexed.</FONT>
</P>

<P><FONT SIZE=3D2>-Eric</FONT>
<BR><FONT SIZE=3D2>-- </FONT>
<BR><FONT SIZE=3D2>Eric Forgette</FONT>
<BR><FONT SIZE=3D2>Unix Systems Administrator</FONT>
<BR><FONT =
SIZE=3D2>_______________________________________________</FONT>
<BR><FONT SIZE=3D2>Veritas-bu maillist&nbsp; -&nbsp; =
Veritas-bu AT mailman.eng.auburn DOT edu</FONT>
<BR><FONT SIZE=3D2><A =
HREF=3D"http://mailman.eng.auburn.edu/mailman/listinfo/veritas-bu"; =
TARGET=3D"_blank">http://mailman.eng.auburn.edu/mailman/listinfo/veritas=
-bu</A></FONT>
</P>

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