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Subject: RE: FS/EVM large I/O support + inverted timeout fixes
Date: Tue, 1 May 2007 11:08:42 -0700
Message-ID: <BB375AF679D4A34E9CA8DFA650E2B04E03797393@onstor-exch02.onstor.net>
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Thread-Topic: FS/EVM large I/O support + inverted timeout fixes
Thread-Index: AceLgM3/IfbgR1gwR/OlgUPQ69MIRgAmVOUg
References: <BB375AF679D4A34E9CA8DFA650E2B04E0379708F@onstor-exch02.onstor.net>
From: "Jonathan Goldick" <jonathan.goldick@onstor.com>
To: "Maxim Kozlovsky" <maxim.kozlovsky@onstor.com>,
	"dl-Cougar" <dl-Cougar@onstor.com>

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1.	In 5.1.3, we may want to change the read behavior described.  If
you get a read in the middle of a file (Spec workload) it's not a great
idea to do a large read starting from that point.  This approach would
likely hurt spec performance, but could be change somewhat to in fact
improve performance.  Does the change you suggest have no impact on
dcache?  At the least we only support a dcache covering 64B, with
alignment rules.  Will that change as well?
2.	In 5.1.4, do you have any guidelines worked out for the various
bobcat modules on how many we will support concurrently?  At the least
we need to spec it so that throughput and Spec do not decrease on these
models.
3.	In 5.2, We should consider that cheetah does not get these
enhancements, or that a core reboot of the FC is a hard failure.  I just
wouldn't want to do much work for an EOL product.
4.	Need a section on limits for the filesystem tune choices.


This should go to dl-designreview as a rule.

_____________________________________________
From: Maxim Kozlovsky=20
Sent: Monday, April 30, 2007 4:40 PM
To: dl-Cougar
Subject: FS/EVM large I/O support + inverted timeout fixes

Here is the brief description of the changes in the file system and EVM
which are going to be done as part of cougar to help us achieve the
performance goals and also fix some insanity in the current code. While
cougar is the reason for the changes, it is entirely possible that we
should ship this with Zonda to continue the Delorean performance
improvements. The fixes for the inverted timeouts and log replay
optimizations should help us to increase the reliability and
availability which is the Zonda goal.

Please send me the comments; we'll schedule the review meeting if
necessary.

Max

 << File: evm.doc >>=20

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<TITLE>RE: FS/EVM large I/O support + inverted timeout fixes</TITLE>
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<P DIR=3DLTR><SPAN LANG=3D"en-us"></SPAN><SPAN LANG=3D"en-us"><FONT =
COLOR=3D"#000080" SIZE=3D2 =
FACE=3D"Arial">1.&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</FONT></SPAN><SPAN =
LANG=3D"en-us"></SPAN><SPAN LANG=3D"en-us"> <FONT COLOR=3D"#000080" =
SIZE=3D2 FACE=3D"Arial">In 5.1.3, we may want to change the read =
behavior described.&nbsp; If you get a read in the middle of a file =
(Spec workload) it</FONT></SPAN><SPAN LANG=3D"en-us"></SPAN><SPAN =
LANG=3D"en-us"><FONT COLOR=3D"#000080" SIZE=3D2 =
FACE=3D"Arial">&#8217;</FONT></SPAN><SPAN LANG=3D"en-us"></SPAN><SPAN =
LANG=3D"en-us"><FONT COLOR=3D"#000080" SIZE=3D2 FACE=3D"Arial">s not a =
great idea to do a large read starting from that point.&nbsp; This =
approach would likely hurt spec performance</FONT></SPAN><SPAN =
LANG=3D"en-us"></SPAN><SPAN LANG=3D"en-us"><FONT COLOR=3D"#000080" =
SIZE=3D2 FACE=3D"Arial">, but could be change somewhat to in fact =
improve performance.&nbsp; Does the change you suggest have no impact on =
dcache?&nbsp; At the least we only support a dcache covering 64B, with =
alignment rules.</FONT></SPAN><SPAN LANG=3D"en-us"></SPAN><SPAN =
LANG=3D"en-us">&nbsp;<FONT COLOR=3D"#000080" SIZE=3D2 FACE=3D"Arial"> =
Will that change as well?</FONT></SPAN><SPAN LANG=3D"en-us"></SPAN><SPAN =
LANG=3D"en-us"></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"></SPAN><SPAN =
LANG=3D"en-us"></SPAN><SPAN LANG=3D"en-us"><FONT COLOR=3D"#000080" =
SIZE=3D2 =
FACE=3D"Arial">2.&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</FONT></SPAN><SPAN =
LANG=3D"en-us"></SPAN><SPAN LANG=3D"en-us"></SPAN><SPAN LANG=3D"en-us"> =
<FONT COLOR=3D"#000080" SIZE=3D2 FACE=3D"Arial">In 5.1.4, do you have =
any guidelines worked out for the various bobcat modules on how many we =
will support concurrently?</FONT></SPAN><SPAN =
LANG=3D"en-us"></SPAN><SPAN LANG=3D"en-us"><FONT COLOR=3D"#000080" =
SIZE=3D2 FACE=3D"Arial">&nbsp; At the least we need to spec it so that =
throughput and Spec do not decrease on these models.</FONT></SPAN><SPAN =
LANG=3D"en-us"></SPAN><SPAN LANG=3D"en-us"></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"></SPAN><SPAN =
LANG=3D"en-us"></SPAN><SPAN LANG=3D"en-us"><FONT COLOR=3D"#000080" =
SIZE=3D2 =
FACE=3D"Arial">3.&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</FONT></SPAN><SPAN =
LANG=3D"en-us"></SPAN><SPAN LANG=3D"en-us"></SPAN><SPAN LANG=3D"en-us"> =
<FONT COLOR=3D"#000080" SIZE=3D2 FACE=3D"Arial">In =
5.2,</FONT></SPAN><SPAN LANG=3D"en-us"></SPAN><SPAN LANG=3D"en-us"> =
<FONT COLOR=3D"#000080" SIZE=3D2 FACE=3D"Arial">We should consider that =
cheetah does not get these enhancements, or that a core reboot of the FC =
is a hard failure.&nbsp; I just wouldn</FONT></SPAN><SPAN =
LANG=3D"en-us"></SPAN><SPAN LANG=3D"en-us"><FONT COLOR=3D"#000080" =
SIZE=3D2 FACE=3D"Arial">&#8217;</FONT></SPAN><SPAN =
LANG=3D"en-us"></SPAN><SPAN LANG=3D"en-us"><FONT COLOR=3D"#000080" =
SIZE=3D2 FACE=3D"Arial">t want to do much work for an EOL =
product.</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"></SPAN><SPAN =
LANG=3D"en-us"></SPAN><SPAN LANG=3D"en-us"><FONT COLOR=3D"#000080" =
SIZE=3D2 =
FACE=3D"Arial">4.&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</FONT></SPAN><SPAN =
LANG=3D"en-us"></SPAN><SPAN LANG=3D"en-us"></SPAN><SPAN LANG=3D"en-us"> =
<FONT COLOR=3D"#000080" SIZE=3D2 FACE=3D"Arial">Need a section on limits =
for the filesystem tune choices.</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"></SPAN><SPAN =
LANG=3D"en-us"></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT COLOR=3D"#000080" SIZE=3D2 =
FACE=3D"Arial">This should go to dl-designreview as a =
rule.</FONT></SPAN><SPAN LANG=3D"en-us"></SPAN><SPAN =
LANG=3D"en-us"></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"></SPAN><SPAN =
LANG=3D"en-us"></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"></SPAN><SPAN =
LANG=3D"en-us"></SPAN><SPAN LANG=3D"en-us"><FONT SIZE=3D2 =
FACE=3D"Tahoma">_____________________________________________<BR>
</FONT></SPAN><SPAN LANG=3D"en-us"><B></B></SPAN><SPAN =
LANG=3D"en-us"><B></B></SPAN><B><SPAN LANG=3D"en-us"><FONT SIZE=3D2 =
FACE=3D"Tahoma">From:</FONT></SPAN></B><SPAN LANG=3D"en-us"></SPAN><SPAN =
LANG=3D"en-us"></SPAN><SPAN LANG=3D"en-us"><FONT SIZE=3D2 =
FACE=3D"Tahoma"> Maxim Kozlovsky<BR>
</FONT></SPAN><SPAN LANG=3D"en-us"><B></B></SPAN><SPAN =
LANG=3D"en-us"><B></B></SPAN><B><SPAN LANG=3D"en-us"><FONT SIZE=3D2 =
FACE=3D"Tahoma">Sent:</FONT></SPAN></B><SPAN LANG=3D"en-us"></SPAN><SPAN =
LANG=3D"en-us"></SPAN><SPAN LANG=3D"en-us"><FONT SIZE=3D2 =
FACE=3D"Tahoma"> Monday, April 30, 2007 4:40 PM<BR>
</FONT></SPAN><SPAN LANG=3D"en-us"><B></B></SPAN><SPAN =
LANG=3D"en-us"><B></B></SPAN><B><SPAN LANG=3D"en-us"><FONT SIZE=3D2 =
FACE=3D"Tahoma">To:</FONT></SPAN></B><SPAN LANG=3D"en-us"></SPAN><SPAN =
LANG=3D"en-us"></SPAN><SPAN LANG=3D"en-us"><FONT SIZE=3D2 =
FACE=3D"Tahoma"> dl-Cougar<BR>
</FONT></SPAN><SPAN LANG=3D"en-us"><B></B></SPAN><SPAN =
LANG=3D"en-us"><B></B></SPAN><B><SPAN LANG=3D"en-us"><FONT SIZE=3D2 =
FACE=3D"Tahoma">Subject:</FONT></SPAN></B><SPAN =
LANG=3D"en-us"></SPAN><SPAN LANG=3D"en-us"></SPAN><SPAN =
LANG=3D"en-us"><FONT SIZE=3D2 FACE=3D"Tahoma"> FS/EVM large I/O support =
+ inverted timeout fixes</FONT></SPAN><SPAN LANG=3D"en-us"></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"></SPAN><SPAN LANG=3D"en-us"><FONT =
SIZE=3D2 FACE=3D"Arial">Here is the brief description of the changes in =
the file system and EVM which are going to be done as part of cougar to =
help us achieve the performance goals and also fix some insanity in the =
current code. While cougar is the reason for the changes, it is entirely =
possible that we should ship this with Zonda to continue the Delorean =
performance improvements. The fixes for the inverted timeouts and log =
replay optimizations should help us to increase the reliability and =
availability which is the Zonda goal.</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT SIZE=3D2 FACE=3D"Arial">Please =
send me the comments; we&#8217;ll schedule the review meeting if =
necessary.</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT SIZE=3D2 =
FACE=3D"Arial">Max</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us">&nbsp;&lt;&lt; File: evm.doc =
&gt;&gt;</SPAN><SPAN LANG=3D"en-us"> </SPAN></P>

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