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Subject: RE: func spec for filesystem layout changes planned in zonda release
Date: Thu, 26 Jul 2007 10:12:25 -0700
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Thread-Topic: func spec for filesystem layout changes planned in zonda release
Thread-Index: AcfOZ1fcj97QLA3/TZyOhVLcbCBEygBNcgvGAAE7YzA=
From: "Sandrine Boulanger" <sandrine.boulanger@onstor.com>
To: "Raj Kumar" <raj.kumar@onstor.com>,
	"Jobi Ariyamannil" <jobi.ariyamannil@onstor.com>,
	"dl-Design Review" <dl-designreview@onstor.com>

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Further comments/questions:

=20

Intro of 5: "If FS does not have many hardlinks, the conversion will be
done instantly" =3D> after how many we're going to need the convert? Is =
it
a total per file or per filesystem?

5.1: will we put hooks in the code to valid all those changes. The only
way to test the behaviors would be through unit tests.

5.2: same comment as 5.1

5.2: how can we make sure that the copy of emap and gennum is not
corrupted before restoring from that copy? Is there a mechanism to make
sure that the copy is complete?

5.2: "Mirror volumes[...] may not need these replicated inodes" =3D> is
the copy created when the mirror is promoted? What happens to the copy
if the mirror is demoted?

5.3: "While extending the inode when truncation is pending, blocks
pending truncation can be resued" =3D> Why? Isn't this risky?

5.4: Is the history log recycled? Should we do it after it reaches a
certain size?

7.1 "Backup should skip bad inodes" =3D> how do we check? Zap some of =
them
and verify backup completes?

=20

=20

=20

________________________________

From: Raj Kumar=20
Sent: Thursday, July 26, 2007 8:54 AM
To: Jobi Ariyamannil; dl-Design Review
Subject: RE: func spec for filesystem layout changes planned in zonda
release

=20

Looks good. Few comments:

=20

* CLI option to set the online EEK schedule is missing

* Is there anything apart from refcount and duplicate data block
corruptions detections planned for Zonda, if yes please mention, helps
us to plan our testing

* Is it feasible to add a functionality to online EEK to do regular EEK
checks but RDONLY?

* should we limit the number of volumes that can be online EEK'd? Since
we are going to support 100 volumes in Zonda, the temptation from the
customers would be to enable this on all volumes, not sure how bad the
performance will be?

=20

________________________________

From: Jobi Ariyamannil
Sent: Tue 7/24/2007 7:56 PM
To: dl-Design Review
Subject: func spec for filesystem layout changes planned in zonda
release

Hi,

=20

Please review the attached func spec for filesystem layout changes
planned for zonda release.

Minor layout changes are made for additional hardening, availability,
recovery and tracing/debugging.

Please let me know any comments you may have.

=20

Regards,

Jobi


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<div class=3DSection1>

<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'>Further =
comments/questions:<o:p></o:p></span></font></p>

<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'><o:p>&nbsp;</o:p></span></font></p>

<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'>Intro of 5: &#8220;If FS does not =
have <i><span
style=3D'font-style:italic'>many</span></i> hardlinks, the conversion =
will be
done instantly&#8221; =3D&gt; after how many we&#8217;re going to need =
the
convert? Is it a total per file or per =
filesystem?<o:p></o:p></span></font></p>

<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'>5.1: will we put hooks in the code =
to
valid all those changes. The only way to test the behaviors would be =
through
unit tests.<o:p></o:p></span></font></p>

<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'>5.2: same comment as =
5.1<o:p></o:p></span></font></p>

<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'>5.2: how can we make sure that the =
copy of
emap and gennum is not corrupted before restoring from that copy? Is =
there a
mechanism to make sure that the copy is =
complete?<o:p></o:p></span></font></p>

<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'>5.2: &#8220;Mirror volumes[&#8230;] =
may
not need these replicated inodes&#8221; =3D&gt; is the copy created when =
the
mirror is promoted? What happens to the copy if the mirror is =
demoted?<o:p></o:p></span></font></p>

<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'>5.3: &#8220;While extending the =
inode when
truncation is pending, blocks pending truncation can be resued&#8221; =
=3D&gt;
Why? Isn&#8217;t this risky?<o:p></o:p></span></font></p>

<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'>5.4: Is the history log recycled? =
Should
we do it after it reaches a certain size?<o:p></o:p></span></font></p>

<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'>7.1 &#8220;Backup should skip bad =
inodes&#8221;
=3D&gt; how do we check? Zap some of them and verify backup =
completes?<o:p></o:p></span></font></p>

<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'><o:p>&nbsp;</o:p></span></font></p>

<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'><o:p>&nbsp;</o:p></span></font></p>

<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'><o:p>&nbsp;</o:p></span></font></p>

<div>

<div class=3DMsoNormal align=3Dcenter style=3D'text-align:center'><font =
size=3D3
face=3D"Times New Roman"><span style=3D'font-size:12.0pt'>

<hr size=3D2 width=3D"100%" align=3Dcenter tabindex=3D-1>

</span></font></div>

<p class=3DMsoNormal><b><font size=3D2 face=3DTahoma><span =
style=3D'font-size:10.0pt;
font-family:Tahoma;font-weight:bold'>From:</span></font></b><font =
size=3D2
face=3DTahoma><span style=3D'font-size:10.0pt;font-family:Tahoma'> Raj =
Kumar <br>
<b><span style=3D'font-weight:bold'>Sent:</span></b> Thursday, July 26, =
2007 8:54
AM<br>
<b><span style=3D'font-weight:bold'>To:</span></b> Jobi Ariyamannil; =
dl-Design
Review<br>
<b><span style=3D'font-weight:bold'>Subject:</span></b> RE: func spec =
for
filesystem layout changes planned in zonda =
release</span></font><o:p></o:p></p>

</div>

<p class=3DMsoNormal><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt'><o:p>&nbsp;</o:p></span></font></p>

<div id=3DidOWAReplyText85612>

<div>

<p class=3DMsoNormal><font size=3D2 color=3Dblack face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:black'>Looks good. Few =
comments:</span></font><o:p></o:p></p>

</div>

<div>

<p class=3DMsoNormal><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt'>&nbsp;<o:p></o:p></span></font></p>

</div>

<div>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'>* CLI option to set the online EEK schedule is =
missing</span></font><o:p></o:p></p>

</div>

<div>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'>* Is there anything apart from refcount and duplicate =
data
block corruptions detections planned for Zonda, if yes please mention, =
helps us
to plan our testing</span></font><o:p></o:p></p>

</div>

<div>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'>* Is it feasible to add a functionality to online EEK =
to do
regular EEK checks but RDONLY?</span></font><o:p></o:p></p>

</div>

<div>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'>* should&nbsp;we limit the number of volumes that can =
be
online EEK'd? Since we are going to support 100 volumes in Zonda, the
temptation from the customers would be to enable this on all volumes, =
not sure
how bad the performance will be?</span></font><o:p></o:p></p>

</div>

</div>

<div>

<p class=3DMsoNormal><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt'><o:p>&nbsp;</o:p></span></font></p>

<div class=3DMsoNormal align=3Dcenter style=3D'text-align:center'><font =
size=3D3
face=3D"Times New Roman"><span style=3D'font-size:12.0pt'>

<hr size=3D2 width=3D"100%" align=3Dcenter tabIndex=3D-1>

</span></font></div>

<p class=3DMsoNormal style=3D'margin-bottom:12.0pt'><b><font size=3D2 =
face=3DTahoma><span
style=3D'font-size:10.0pt;font-family:Tahoma;font-weight:bold'>From:</spa=
n></font></b><font
size=3D2 face=3DTahoma><span =
style=3D'font-size:10.0pt;font-family:Tahoma'> Jobi
Ariyamannil<br>
<b><span style=3D'font-weight:bold'>Sent:</span></b> Tue 7/24/2007 7:56 =
PM<br>
<b><span style=3D'font-weight:bold'>To:</span></b> dl-Design Review<br>
<b><span style=3D'font-weight:bold'>Subject:</span></b> func spec for =
filesystem
layout changes planned in zonda release</span></font><o:p></o:p></p>

</div>

<div>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'>Hi,</span></font><o:p></o:p></p>

<p class=3DMsoNormal><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt'>&nbsp;<o:p></o:p></span></font></p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'>Please review the attached func spec for filesystem =
layout
changes planned for zonda release.</span></font><o:p></o:p></p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'>Minor layout changes are made for additional =
hardening,
availability, recovery and =
tracing/debugging.</span></font><o:p></o:p></p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'>Please let me know any comments you may =
have.</span></font><o:p></o:p></p>

<p class=3DMsoNormal><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt'>&nbsp;<o:p></o:p></span></font></p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'>Regards,</span></font><o:p></o:p></p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'>Jobi</span></font><o:p></o:p></p>

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