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Subject: RE: snapshot autoremove question
Date: Tue, 13 Nov 2007 20:06:46 -0800
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Thread-Topic: snapshot autoremove question
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From: "Paul Hammer" <paul.hammer@onstor.com>
To: "Narayan Venkat" <narayan.venkat@onstor.com>,
	"Eric Barrett" <eric.barrett@onstor.com>,
	"Tim Gardner" <tim.gardner@onstor.com>,
	"Joshua Goldenhar" <joshua.goldenhar@onstor.com>,
	"Henry Lau" <henry.lau@onstor.com>,
	"dl-Design Review" <dl-designreview@onstor.com>
Cc: "Sandrine Boulanger" <sandrine.boulanger@onstor.com>,
	"Vikas Saini" <vikas.saini@onstor.com>,
	"Manohar Divate" <manohar.divate@onstor.com>,
	"Dennis Arellano" <dennis.arellano@onstor.com>

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The data loss point is from me.
=20
The MRD states:
Auto Remove Snapshots. We need a configurable ability to auto remove =
snapshots when filesystem gets full.
=20
Now we are going down a path of deleting snapshots at any water mark and =
not conditionaly as the MRD stated when the file system is full.  If =
this is what is/was really wanted we should have captured that in the =
MRD, at this point the spec and the MRD don't agree. Which is correct?
=20
-Paul

________________________________

From: Narayan Venkat
Sent: Tue 11/13/2007 5:03 PM
To: Eric Barrett; Tim Gardner; Paul Hammer; Joshua Goldenhar; Henry Lau; =
dl-Design Review
Cc: Sandrine Boulanger; Vikas Saini; Manohar Divate; Dennis Arellano
Subject: RE: snapshot autoremove question



Since I am not in dl-design review, I am seeing this thread late.  I =
agree with Eric's statements that we should not impose an arbitrary =
requirement of autogrow before deleting a snapshot.  Where is the =
"secondary data loss" argument coming from?  I don't understand it.  Why =
would we lose data if snapshot reclamation and Autogrow work as =
designed?  What am I missing?

=20

I'd vote for keeping the design in such a way that Autogrow and Snapshot =
removal are independent and tunable separately.  This is how other =
vendors do it. =20

=20

Narayan Venkat=20
Vice President, Marketing=20
ONStor, Inc.=20
Tel: (408) 963-2404=20
Cell: (408) 221-4297.=20

________________________________

From: Eric Barrett=20
Sent: Monday, November 12, 2007 8:58 AM
To: Tim Gardner; Paul Hammer; Joshua Goldenhar; Henry Lau; dl-Design =
Review
Cc: Sandrine Boulanger; Vikas Saini; Manohar Divate; Dennis Arellano
Subject: RE: snapshot autoremove question

=20

I have to add also that I don't agree with the "secondary data loss" =
argument.  ARHWM would be elective and therefore no different than any =
other cleanup job, such as a Unix system sweeping up files in /tmp, or a =
job to delete backup archive images.

=20

=20

________________________________

From: Eric Barrett=20
Sent: Monday, November 12, 2007 8:54 AM
To: Tim Gardner; Paul Hammer; Joshua Goldenhar; Henry Lau; dl-Design =
Review
Cc: Sandrine Boulanger; Vikas Saini; Manohar Divate; Dennis Arellano
Subject: RE: snapshot autoremove question

My feedback to Henry before the meeting was that as an admin, I'd be =
pissed at the arbitrary requirement that I autogrow stuff before I =
automatically delete snapshots.  My own personal preference would be to =
delete snapshots first.  I can't imagine I'm the only one.

=20

This is especially true since the implementation was changed so that we =
do NOT guarantee the user does not receive ENOSPC because of a =
snapshot's disk consumption.

=20

If linking ARHWM and AGHWM increases complexity of the user interaction, =
complexity of user understanding, complexity of testing, complexity of =
implementation, AND in the end results in a LOSS of functionality, why =
do it that way?

=20

=20

________________________________

From: Tim Gardner=20
Sent: Friday, November 09, 2007 11:15 PM
To: Paul Hammer; Joshua Goldenhar; Henry Lau; dl-Design Review
Cc: Sandrine Boulanger; Vikas Saini; Manohar Divate; Dennis Arellano
Subject: RE: snapshot autoremove question

Paul,

=20

This idea was discussed in detail during the design review. The =
conclusion was that autogrow and

auto snapshot removal should not be coupled for several reasons.

=20

Coupling them significantly increases the complexity of the design and =
implementation.

It will result in more test cases, not less, than the current proposal.

It will increase the complexity of the documentation.

It is more likely to result in support calls.

=20

Consider the workflow where a user sets an ARHWM of 80% with autogrow =
disabled.

What do we do when the user later enables autogrow with a 90% HWM?

Do we disable snapshot auro removal because it has a lower HWM?

Do we silently ignore the 80% HWM and instead use a HWM above 90%?

Do we outright change the HWM to something larger then 80%?

De we set if back if autogrow is later disabled?

What HWM do we display to the user when a vol show is done?

=20

It was also thought that customers may want to intentionally set the =
ARHWM lower than

the autogrow HWM. Without actually asking customers, we really don't =
know.

The consensus was that we should give customers the choice and utilize =
the best

practices guide to document implications of various settings.

=20

Tim


=20

________________________________

From: Paul Hammer
Sent: Fri 11/9/2007 8:46 PM
To: Joshua Goldenhar; Henry Lau; dl-Design Review
Cc: Sandrine Boulanger; Vikas Saini; Manohar Divate; Dennis Arellano
Subject: RE: snapshot autoremove question

Hi All,

=20

Like to have the design changed slightly, think that if the user has =
autogrow enabled that the HWM to trigger a snapshot deletion cannot be =
set to a lower value then the autogrow value (we do not want to lose =
secondary data sets, that is essentially data loss), the code must catch =
this issue and trigger an error message and prevent the cfg. The =
marketing  requirement (not spec) was to free up space by deleting =
snapshots if the customer was going to run out of disk space (i.e. =
autogrow turned off or out of luns with autogrow on), the requirement =
was not about when the deletion should be triggered (at what amount of =
capacity was left) or allowing a HWM for activating the deletion. Having =
the delete happen before the autogrow adds to many unnecessary test =
permutations.  Granted QA must test the condition where AG is set to on =
and no free luns are available, if the delete snapshots option is set in =
this case then the Snapshot  will be deleted to buy some head room.

=20

Please keep in mind what the requirement stated (not the spec), don't =
want to get into a protracted discussion on would we allow snapshots to =
be deleted at any HWM, that would be a very different different =
requirement.

=20

If the user is going without autogrow being enabled they can set the HWM =
to delete snapshots to what ever value they want, would be surprised =
that anyone would set it at anything other than 98% or so (given what =
the requirment states).

=20

Thanks,

=20

-Paul

=20

________________________________

From: Joshua Goldenhar
Sent: Fri 11/9/2007 1:25 PM
To: Henry Lau; dl-Design Review
Cc: Sandrine Boulanger; Vikas Saini; Manohar Divate; Dennis Arellano
Subject: RE: snapshot autoremove question

Thanks Henry - I see that this mentions the fact that you cannot pin =
scheduled snapshots and mentions setting autogrow in such a way that =
infers it is independent.

=20

I'm sure Dennis will work his magic to turn this into fabulous =
documentation ;-)

-Josh=20

Josh Goldenhar=20
Phone: 408 963 2408, Cell: 408 547 7693=20

________________________________

From: Henry Lau=20
Sent: Friday, November 09, 2007 11:53 AM
To: Joshua Goldenhar; dl-Design Review
Cc: Sandrine Boulanger; Vikas Saini; Manohar Divate
Subject: RE: snapshot autoremove question

=20

Hi Joshua,

=20

Please check the best practice section in section 8.1 of the doc.        =
    =20

=20

/n/software/FileSystem/snapshot_management_R98_autoremove.doc

=20

Thanks,

Henry

=20

________________________________

From: Joshua Goldenhar=20
Sent: Friday, November 09, 2007 11:35 AM
To: Jobi Ariyamannil; John Keiffer; dl-Design Review
Cc: Sandrine Boulanger; Vikas Saini; Manohar Divate
Subject: RE: snapshot autoremove question

=20

Thanks Jobi.

=20

These types of questions came up in the last design review and were =
discussed at length.

=20

I think a simple rewording of your problem statement can illuminate the =
overall design principle we ended up sticking to:

"I would like to understand why we are willing to possibly delete all of =
a customer's snapshots, if they have set and reached their autoremoval =
high water mark (ARHWM)." Becomes: "...why is the customer willing to =
possibly delete all of their snapshots..."

=20

As Jobi mentioned, the customer optionally turns this feature on. It's =
our job to make sure the documentation and best practices guides issue =
this warning and make operation as clear and understandable as possible.

=20

If we come up with an arbitrary algorithm to preserve snapshots, there =
will always be a customer that will say "why did you do it THAT way? - I =
would rather have had XYZ..."=20

=20

I did not know we cannot pin the scheduled snapshots - I imagine we'll =
get an RFE in the future to auto-pin snapshots or set a preservation =
threshold on scheduled snapshots.=20

=20

For now though I really feel the simplicity of the feature as =
implemented makes it easy to understand and makes the "dangers" easy to =
understand also.

-Josh=20

Josh Goldenhar=20
Phone: 408 963 2408, Cell: 408 547 7693=20

________________________________

From: Jobi Ariyamannil=20
Sent: Friday, November 09, 2007 10:13 AM
To: John Keiffer; dl-Design Review
Cc: Sandrine Boulanger; Vikas Saini; Manohar Divate
Subject: RE: snapshot autoremove question

=20

Snapshot auto removal is an optional feature somebody needs to turn on.  =
If they set the HWM too low, they may end up losing the snapshots.

I don't see any need of setting that below 98%.  The need for removing =
snapshots automatically is needed when filesystem operates in close to =
full conditions and prevent applications running into ENOSPC because of =
the space pinned by snapshots.  By providing an option for the user to =
specify that threshold, we ended up with all these interesting =
possibilities.

=20

Regards,

Jobi

=20

________________________________

From: John Keiffer=20
Sent: Friday, November 09, 2007 10:05 AM
To: dl-Design Review
Cc: Sandrine Boulanger; Vikas Saini; Manohar Divate
Subject: snapshot autoremove question

[opens mouth]

=20

I would like to understand why we are willing to possibly delete all of =
a customer's snapshots, if they have set and reached their autoremoval =
high water mark (ARHWM).=20

=20

It seems that if users in the field are keeping a lot of snapshots that =
this might not be a problem, since deleting some might free up the =
necessary space. If users in the field are only scheduling a smaller =
number of snapshots to be taken it is more likely that we might end up =
deleting them all.=20

=20

Example problem: I ran it an issue where after creating a large file =
(using pre-allocation), my volume usage was over the ARHWM. I then =
deleted the large file. However, because both the snapshot deletion and =
file deletion happen in the background, the snapshots deletion happened =
before the large file was removed and the volume usage went back down. =
So I ended up losing my file and my snapshots.

=20

Since we cannot pin weekly, daily, or hourly snapshots, and they are =
likely to be the most current, it seems like we should keep at least =
one. Some of us in QA think it might be nice to keep one of each, but at =
a minimum it seems that we should at least keep the most current. If the =
last unpinned snapshot needs to be deleted in order to free up space, =
there are bigger issues to deal with.

=20

[inserts foot]

=20

Thank you,

John Keiffer

=20

=20


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<DIV id=3DidOWAReplyText77646 dir=3Dltr>=0A=
<DIV dir=3Dltr><FONT face=3DArial color=3D#000000 size=3D2>The data loss =
point is from me.</FONT></DIV>=0A=
<DIV dir=3Dltr><FONT face=3DArial size=3D2></FONT>&nbsp;</DIV>=0A=
<DIV dir=3Dltr><FONT face=3DArial color=3D#000000 size=3D2>The MRD =
states:</FONT></DIV>=0A=
<DIV dir=3Dltr><FONT face=3DArial color=3D#000000 =
size=3D2><STRONG><EM>Auto Remove Snapshots. We need a configurable =
ability to auto remove snapshots when filesystem gets =
full.</EM></STRONG></FONT></DIV>=0A=
<DIV dir=3Dltr><FONT face=3DArial size=3D2></FONT>&nbsp;</DIV>=0A=
<DIV dir=3Dltr><FONT face=3DArial size=3D2>Now we are going down a path =
of deleting snapshots at any water mark and not conditionaly as the MRD =
stated when the file system is full.&nbsp;&nbsp;If this is what is/was =
really wanted we should have captured that in the MRD, at this point the =
spec and the MRD don't agree. Which is correct?</FONT></DIV>=0A=
<DIV dir=3Dltr><FONT face=3DArial size=3D2></FONT>&nbsp;</DIV>=0A=
<DIV dir=3Dltr><FONT face=3DArial size=3D2>-Paul</FONT></DIV></DIV>=0A=
<DIV dir=3Dltr><BR>=0A=
<HR tabIndex=3D-1>=0A=
<FONT face=3DTahoma size=3D2><B>From:</B> Narayan Venkat<BR><B>Sent:</B> =
Tue 11/13/2007 5:03 PM<BR><B>To:</B> Eric Barrett; Tim Gardner; Paul =
Hammer; Joshua Goldenhar; Henry Lau; dl-Design Review<BR><B>Cc:</B> =
Sandrine Boulanger; Vikas Saini; Manohar Divate; Dennis =
Arellano<BR><B>Subject:</B> RE: snapshot autoremove =
question<BR></FONT><BR></DIV>=0A=
<DIV>=0A=
<DIV class=3DSection1>=0A=
<P class=3DMsoNormal><FONT face=3DArial color=3Dnavy size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">Since I am =
not in dl-design review, I am seeing this thread late. &nbsp;I agree =
with Eric&#8217;s statements that we should not impose an arbitrary =
requirement of autogrow before deleting a snapshot. &nbsp;Where is the =
&#8220;secondary data loss&#8221; argument coming from? &nbsp;I =
don&#8217;t understand it.&nbsp; Why would we lose data if snapshot =
reclamation and Autogrow work as designed?&nbsp; What am I =
missing?</SPAN></FONT></P>=0A=
<P class=3DMsoNormal><FONT face=3DArial color=3Dnavy size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: =
Arial"></SPAN></FONT>&nbsp;</P>=0A=
<P class=3DMsoNormal><FONT face=3DArial color=3Dnavy size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">I&#8217;d =
vote for keeping the design in such a way that Autogrow and Snapshot =
removal are independent and tunable separately. &nbsp;This is how other =
vendors do it. &nbsp;</SPAN></FONT></P>=0A=
<P class=3DMsoNormal><FONT face=3DArial color=3Dnavy size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: =
Arial"></SPAN></FONT>&nbsp;</P>=0A=
<DIV>=0A=
<P><FONT face=3DArial color=3Dnavy size=3D2><SPAN style=3D"FONT-SIZE: =
10pt; COLOR: navy; FONT-FAMILY: Arial">Narayan Venkat</SPAN></FONT><FONT =
color=3Dnavy><SPAN style=3D"COLOR: navy"> <BR></SPAN></FONT><FONT =
face=3DArial color=3Dnavy size=3D2><SPAN style=3D"FONT-SIZE: 10pt; =
COLOR: navy; FONT-FAMILY: Arial">Vice President, =
Marketing</SPAN></FONT><FONT color=3Dnavy><SPAN style=3D"COLOR: navy"> =
<BR></SPAN></FONT><FONT face=3DArial color=3Dnavy size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">ONStor, =
Inc.</SPAN></FONT><FONT color=3Dnavy><SPAN style=3D"COLOR: navy"> =
<BR></SPAN></FONT><FONT face=3DArial color=3Dnavy size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">Tel: (408) =
963-2404</SPAN></FONT><FONT color=3Dnavy><SPAN style=3D"COLOR: navy"> =
<BR></SPAN></FONT><FONT face=3DArial color=3Dnavy size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">Cell: (408) =
221-4297.</SPAN></FONT><FONT color=3Dnavy><SPAN style=3D"COLOR: navy"> =
</SPAN></FONT></P></DIV>=0A=
<DIV>=0A=
<DIV class=3DMsoNormal style=3D"TEXT-ALIGN: center" align=3Dcenter><FONT =
face=3D"Times New Roman" size=3D3><SPAN style=3D"FONT-SIZE: 12pt">=0A=
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<P class=3DMsoNormal><B><FONT face=3DTahoma size=3D2><SPAN =
style=3D"FONT-WEIGHT: bold; FONT-SIZE: 10pt; FONT-FAMILY: =
Tahoma">From:</SPAN></FONT></B><FONT face=3DTahoma size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Tahoma"> Eric Barrett =
<BR><B><SPAN style=3D"FONT-WEIGHT: bold">Sent:</SPAN></B> Monday, =
November 12, 2007 8:58 AM<BR><B><SPAN style=3D"FONT-WEIGHT: =
bold">To:</SPAN></B> Tim Gardner; Paul Hammer; Joshua Goldenhar; Henry =
Lau; dl-Design Review<BR><B><SPAN style=3D"FONT-WEIGHT: =
bold">Cc:</SPAN></B> Sandrine Boulanger; Vikas Saini; Manohar Divate; =
Dennis Arellano<BR><B><SPAN style=3D"FONT-WEIGHT: =
bold">Subject:</SPAN></B> RE: snapshot autoremove =
question</SPAN></FONT></P></DIV>=0A=
<P class=3DMsoNormal><FONT face=3D"Times New Roman" size=3D3><SPAN =
style=3D"FONT-SIZE: 12pt"></SPAN></FONT>&nbsp;</P>=0A=
<P class=3DMsoNormal><FONT face=3DArial size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">I have to add also that I =
don't agree with the "secondary data loss" argument.&nbsp; ARHWM would =
be elective and therefore no different than any other cleanup job, such =
as a Unix system sweeping up files in /tmp, or a job to delete backup =
archive images.</SPAN></FONT></P>=0A=
<P class=3DMsoNormal><FONT face=3D"Times New Roman" size=3D3><SPAN =
style=3D"FONT-SIZE: 12pt"></SPAN></FONT>&nbsp;</P>=0A=
<P class=3DMsoNormal><FONT face=3D"Times New Roman" size=3D3><SPAN =
style=3D"FONT-SIZE: 12pt"></SPAN></FONT>&nbsp;</P>=0A=
<DIV class=3DMsoNormal style=3D"TEXT-ALIGN: center" align=3Dcenter><FONT =
face=3D"Times New Roman" size=3D3><SPAN style=3D"FONT-SIZE: 12pt">=0A=
<HR tabIndex=3D-1 align=3Dcenter width=3D"100%" SIZE=3D2>=0A=
</SPAN></FONT></DIV>=0A=
<P class=3DMsoNormal style=3D"MARGIN-BOTTOM: 12pt"><B><FONT =
face=3DTahoma size=3D2><SPAN style=3D"FONT-WEIGHT: bold; FONT-SIZE: =
10pt; FONT-FAMILY: Tahoma">From:</SPAN></FONT></B><FONT face=3DTahoma =
size=3D2><SPAN style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Tahoma"> Eric =
Barrett <BR><B><SPAN style=3D"FONT-WEIGHT: bold">Sent:</SPAN></B> =
Monday, November 12, 2007 8:54 AM<BR><B><SPAN style=3D"FONT-WEIGHT: =
bold">To:</SPAN></B> Tim Gardner; Paul Hammer; Joshua Goldenhar; Henry =
Lau; dl-Design Review<BR><B><SPAN style=3D"FONT-WEIGHT: =
bold">Cc:</SPAN></B> Sandrine Boulanger; Vikas Saini; Manohar Divate; =
Dennis Arellano<BR><B><SPAN style=3D"FONT-WEIGHT: =
bold">Subject:</SPAN></B> RE: snapshot autoremove =
question</SPAN></FONT></P>=0A=
<P class=3DMsoNormal><FONT face=3DArial size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">My feedback to Henry =
before the meeting was that as an admin, I'd be pissed at the arbitrary =
requirement that I autogrow stuff before I automatically delete =
snapshots.&nbsp; My own personal preference would be to delete snapshots =
first.&nbsp; I can't imagine I'm the only one.</SPAN></FONT></P>=0A=
<P class=3DMsoNormal><FONT face=3D"Times New Roman" size=3D3><SPAN =
style=3D"FONT-SIZE: 12pt"></SPAN></FONT>&nbsp;</P>=0A=
<P class=3DMsoNormal><FONT face=3DArial size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">This is especially =
true&nbsp;since the implementation was changed so that we do NOT =
guarantee the user does not receive ENOSPC because of a snapshot's disk =
consumption.</SPAN></FONT></P>=0A=
<P class=3DMsoNormal><FONT face=3D"Times New Roman" size=3D3><SPAN =
style=3D"FONT-SIZE: 12pt"></SPAN></FONT>&nbsp;</P>=0A=
<P class=3DMsoNormal><FONT face=3DArial size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">If linking ARHWM and AGHWM =
increases complexity of the user interaction, complexity of user =
understanding, complexity of testing, complexity of implementation, AND =
in the end results in a LOSS of functionality, why do it that =
way?</SPAN></FONT></P>=0A=
<P class=3DMsoNormal><FONT face=3D"Times New Roman" size=3D3><SPAN =
style=3D"FONT-SIZE: 12pt"></SPAN></FONT>&nbsp;</P>=0A=
<P class=3DMsoNormal><FONT face=3D"Times New Roman" size=3D3><SPAN =
style=3D"FONT-SIZE: 12pt"></SPAN></FONT>&nbsp;</P>=0A=
<DIV class=3DMsoNormal style=3D"TEXT-ALIGN: center" align=3Dcenter><FONT =
face=3D"Times New Roman" size=3D3><SPAN style=3D"FONT-SIZE: 12pt">=0A=
<HR tabIndex=3D-1 align=3Dcenter width=3D"100%" SIZE=3D2>=0A=
</SPAN></FONT></DIV>=0A=
<P class=3DMsoNormal style=3D"MARGIN-BOTTOM: 12pt"><B><FONT =
face=3DTahoma size=3D2><SPAN style=3D"FONT-WEIGHT: bold; FONT-SIZE: =
10pt; FONT-FAMILY: Tahoma">From:</SPAN></FONT></B><FONT face=3DTahoma =
size=3D2><SPAN style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Tahoma"> Tim =
Gardner <BR><B><SPAN style=3D"FONT-WEIGHT: bold">Sent:</SPAN></B> =
Friday, November 09, 2007 11:15 PM<BR><B><SPAN style=3D"FONT-WEIGHT: =
bold">To:</SPAN></B> Paul Hammer; Joshua Goldenhar; Henry Lau; dl-Design =
Review<BR><B><SPAN style=3D"FONT-WEIGHT: bold">Cc:</SPAN></B> Sandrine =
Boulanger; Vikas Saini; Manohar Divate; Dennis Arellano<BR><B><SPAN =
style=3D"FONT-WEIGHT: bold">Subject:</SPAN></B> RE: snapshot autoremove =
question</SPAN></FONT></P>=0A=
<DIV id=3DidOWAReplyText8728>=0A=
<DIV>=0A=
<P class=3DMsoNormal><FONT face=3DArial size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: =
Arial">Paul,</SPAN></FONT></P></DIV>=0A=
<DIV>=0A=
<P class=3DMsoNormal><FONT face=3D"Times New Roman" size=3D3><SPAN =
style=3D"FONT-SIZE: 12pt"></SPAN></FONT>&nbsp;</P></DIV>=0A=
<DIV>=0A=
<P class=3DMsoNormal><FONT face=3DArial size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">This idea was discussed in =
detail during the design review. The conclusion was that autogrow =
and</SPAN></FONT></P></DIV>=0A=
<DIV>=0A=
<P class=3DMsoNormal><FONT face=3DArial size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">auto snapshot removal =
should not be coupled for several reasons.</SPAN></FONT></P></DIV>=0A=
<DIV>=0A=
<P class=3DMsoNormal><FONT face=3D"Times New Roman" size=3D3><SPAN =
style=3D"FONT-SIZE: 12pt"></SPAN></FONT>&nbsp;</P></DIV>=0A=
<DIV>=0A=
<P class=3DMsoNormal><FONT face=3DArial size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">Coupling them =
significantly increases the complexity of the design and =
implementation.</SPAN></FONT></P></DIV>=0A=
<DIV>=0A=
<P class=3DMsoNormal><FONT face=3DArial size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">It will result in more =
test cases, not less, than the current proposal.</SPAN></FONT></P></DIV>=0A=
<DIV>=0A=
<P class=3DMsoNormal><FONT face=3DArial size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">It will increase the =
complexity of the documentation.</SPAN></FONT></P></DIV>=0A=
<DIV>=0A=
<P class=3DMsoNormal><FONT face=3DArial size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">It is more likely to =
result in support calls.</SPAN></FONT></P></DIV>=0A=
<DIV>=0A=
<P class=3DMsoNormal><FONT face=3D"Times New Roman" size=3D3><SPAN =
style=3D"FONT-SIZE: 12pt"></SPAN></FONT>&nbsp;</P></DIV>=0A=
<DIV>=0A=
<P class=3DMsoNormal><FONT face=3DArial size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">Consider the workflow =
where a user sets an ARHWM of 80% with autogrow =
disabled.</SPAN></FONT></P></DIV>=0A=
<DIV>=0A=
<P class=3DMsoNormal><FONT face=3DArial size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">What do we do when the =
user later enables autogrow with a 90% HWM?</SPAN></FONT></P></DIV>=0A=
<DIV>=0A=
<P class=3DMsoNormal><FONT face=3DArial size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">Do we disable snapshot =
auro removal because it has a lower HWM?</SPAN></FONT></P></DIV>=0A=
<DIV>=0A=
<P class=3DMsoNormal><FONT face=3DArial size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">Do we silently ignore the =
80% HWM and instead use a HWM above 90%?</SPAN></FONT></P></DIV>=0A=
<DIV>=0A=
<P class=3DMsoNormal><FONT face=3DArial size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">Do we outright change the =
HWM to something larger then 80%?</SPAN></FONT></P></DIV>=0A=
<DIV>=0A=
<P class=3DMsoNormal><FONT face=3DArial size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">De we set if back if =
autogrow is later disabled?</SPAN></FONT></P></DIV>=0A=
<DIV>=0A=
<P class=3DMsoNormal><FONT face=3DArial size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">What HWM do we display to =
the user when a vol show is done?</SPAN></FONT></P></DIV>=0A=
<DIV>=0A=
<P class=3DMsoNormal><FONT face=3D"Times New Roman" size=3D3><SPAN =
style=3D"FONT-SIZE: 12pt"></SPAN></FONT>&nbsp;</P></DIV>=0A=
<DIV>=0A=
<P class=3DMsoNormal><FONT face=3DArial size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">It was also thought that =
customers may want to intentionally set the ARHWM lower =
than</SPAN></FONT></P></DIV>=0A=
<DIV>=0A=
<P class=3DMsoNormal><FONT face=3DArial size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">the autogrow HWM. Without =
actually asking customers, we really don't know.</SPAN></FONT></P></DIV>=0A=
<DIV>=0A=
<P class=3DMsoNormal><FONT face=3DArial size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">The consensus was that we =
should give customers the choice and utilize the =
best</SPAN></FONT></P></DIV>=0A=
<DIV>=0A=
<P class=3DMsoNormal><FONT face=3DArial size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">practices guide to =
document implications of various settings.</SPAN></FONT></P></DIV>=0A=
<DIV>=0A=
<P class=3DMsoNormal><FONT face=3D"Times New Roman" size=3D3><SPAN =
style=3D"FONT-SIZE: 12pt"></SPAN></FONT>&nbsp;</P></DIV>=0A=
<DIV>=0A=
<P class=3DMsoNormal><FONT face=3D"Times New Roman" size=3D3><SPAN =
style=3D"FONT-SIZE: 12pt">Tim</SPAN></FONT></P></DIV>=0A=
<DIV>=0A=
<P class=3DMsoNormal><FONT face=3D"Times New Roman" size=3D3><SPAN =
style=3D"FONT-SIZE: 12pt"><BR>&nbsp;</SPAN></FONT></P></DIV>=0A=
<DIV>=0A=
<DIV class=3DMsoNormal style=3D"TEXT-ALIGN: center" align=3Dcenter><FONT =
face=3D"Times New Roman" size=3D3><SPAN style=3D"FONT-SIZE: 12pt">=0A=
<HR tabIndex=3D-1 align=3Dcenter width=3D"100%" SIZE=3D2>=0A=
</SPAN></FONT></DIV></DIV>=0A=
<DIV>=0A=
<P class=3DMsoNormal style=3D"MARGIN-BOTTOM: 12pt"><B><FONT =
face=3DTahoma size=3D2><SPAN style=3D"FONT-WEIGHT: bold; FONT-SIZE: =
10pt; FONT-FAMILY: Tahoma">From:</SPAN></FONT></B><FONT face=3DTahoma =
size=3D2><SPAN style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Tahoma"> Paul =
Hammer<BR><B><SPAN style=3D"FONT-WEIGHT: bold">Sent:</SPAN></B> Fri =
11/9/2007 8:46 PM<BR><B><SPAN style=3D"FONT-WEIGHT: bold">To:</SPAN></B> =
Joshua Goldenhar; Henry Lau; dl-Design Review<BR><B><SPAN =
style=3D"FONT-WEIGHT: bold">Cc:</SPAN></B> Sandrine Boulanger; Vikas =
Saini; Manohar Divate; Dennis Arellano<BR><B><SPAN style=3D"FONT-WEIGHT: =
bold">Subject:</SPAN></B> RE: snapshot autoremove =
question</SPAN></FONT></P></DIV></DIV>=0A=
<DIV>=0A=
<DIV id=3DidOWAReplyText11426>=0A=
<DIV>=0A=
<P class=3DMsoNormal><FONT face=3DArial size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">Hi =
All,</SPAN></FONT></P></DIV>=0A=
<DIV>=0A=
<P class=3DMsoNormal><FONT face=3D"Times New Roman" size=3D3><SPAN =
style=3D"FONT-SIZE: 12pt"></SPAN></FONT>&nbsp;</P></DIV>=0A=
<DIV>=0A=
<P class=3DMsoNormal><FONT face=3DArial size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">Like to have the design =
changed slightly, think that if the user has autogrow enabled that the =
HWM to trigger a snapshot deletion cannot be set to a lower value then =
the autogrow value (we do not want to lose secondary data sets, that is =
essentially data loss),&nbsp;the code must catch this issue and trigger =
an error message and prevent the cfg. The marketing &nbsp;requirement =
(not spec) was to free up space by deleting snapshots if the customer =
was going to run out of disk space (i.e. autogrow turned off or out of =
luns with autogrow on), the requirement was not about when the deletion =
should be triggered (at what amount of capacity was left) or allowing a =
HWM for activating the deletion. Having the delete happen before the =
autogrow adds to many unnecessary test permutations.&nbsp; Granted QA =
must test the condition where AG is set to on and no free luns are =
available, if the delete snapshots option is set in this case then the =
Snapshot &nbsp;will be deleted to buy some head =
room.</SPAN></FONT></P></DIV>=0A=
<DIV>=0A=
<P class=3DMsoNormal><FONT face=3D"Times New Roman" size=3D3><SPAN =
style=3D"FONT-SIZE: 12pt"></SPAN></FONT>&nbsp;</P></DIV>=0A=
<DIV>=0A=
<P class=3DMsoNormal><FONT face=3DArial size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">Please keep in mind what =
the requirement stated (not the spec), don't want to get into a =
protracted discussion on would we allow snapshots to be deleted at any =
HWM, that would be a very different different =
requirement.</SPAN></FONT></P></DIV>=0A=
<DIV>=0A=
<P class=3DMsoNormal><FONT face=3D"Times New Roman" size=3D3><SPAN =
style=3D"FONT-SIZE: 12pt"></SPAN></FONT>&nbsp;</P></DIV>=0A=
<DIV>=0A=
<P class=3DMsoNormal><FONT face=3DArial size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">If the user is going =
without autogrow being enabled they can set the HWM to delete snapshots =
to what ever value they want, would be surprised that anyone would set =
it at anything other than 98% or so (given what the requirment =
states).</SPAN></FONT></P></DIV>=0A=
<DIV>=0A=
<P class=3DMsoNormal><FONT face=3D"Times New Roman" size=3D3><SPAN =
style=3D"FONT-SIZE: 12pt"></SPAN></FONT>&nbsp;</P></DIV>=0A=
<DIV>=0A=
<P class=3DMsoNormal><FONT face=3DArial size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: =
Arial">Thanks,</SPAN></FONT></P></DIV>=0A=
<DIV>=0A=
<P class=3DMsoNormal><FONT face=3D"Times New Roman" size=3D3><SPAN =
style=3D"FONT-SIZE: 12pt"></SPAN></FONT>&nbsp;</P></DIV>=0A=
<DIV>=0A=
<P class=3DMsoNormal><FONT face=3DArial size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: =
Arial">-Paul</SPAN></FONT></P></DIV></DIV>=0A=
<DIV>=0A=
<P class=3DMsoNormal><FONT face=3D"Times New Roman" size=3D3><SPAN =
style=3D"FONT-SIZE: 12pt"></SPAN></FONT>&nbsp;</P>=0A=
<DIV class=3DMsoNormal style=3D"TEXT-ALIGN: center" align=3Dcenter><FONT =
face=3D"Times New Roman" size=3D3><SPAN style=3D"FONT-SIZE: 12pt">=0A=
<HR tabIndex=3D-1 align=3Dcenter width=3D"100%" SIZE=3D2>=0A=
</SPAN></FONT></DIV>=0A=
<P class=3DMsoNormal style=3D"MARGIN-BOTTOM: 12pt"><B><FONT =
face=3DTahoma size=3D2><SPAN style=3D"FONT-WEIGHT: bold; FONT-SIZE: =
10pt; FONT-FAMILY: Tahoma">From:</SPAN></FONT></B><FONT face=3DTahoma =
size=3D2><SPAN style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Tahoma"> Joshua =
Goldenhar<BR><B><SPAN style=3D"FONT-WEIGHT: bold">Sent:</SPAN></B> Fri =
11/9/2007 1:25 PM<BR><B><SPAN style=3D"FONT-WEIGHT: bold">To:</SPAN></B> =
Henry Lau; dl-Design Review<BR><B><SPAN style=3D"FONT-WEIGHT: =
bold">Cc:</SPAN></B> Sandrine Boulanger; Vikas Saini; Manohar Divate; =
Dennis Arellano<BR><B><SPAN style=3D"FONT-WEIGHT: =
bold">Subject:</SPAN></B> RE: snapshot autoremove =
question</SPAN></FONT></P></DIV>=0A=
<DIV>=0A=
<P class=3DMsoNormal><FONT face=3DArial color=3Dnavy size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">Thanks Henry =
&#8211; I see that this mentions the fact that you cannot pin scheduled =
snapshots and mentions setting autogrow in such a way that infers it is =
independent.</SPAN></FONT></P>=0A=
<P class=3DMsoNormal><FONT face=3D"Times New Roman" size=3D3><SPAN =
style=3D"FONT-SIZE: 12pt"></SPAN></FONT>&nbsp;</P>=0A=
<P class=3DMsoNormal><FONT face=3DArial color=3Dnavy size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">I&#8217;m =
sure Dennis will work his magic to turn this into fabulous documentation =
;-)</SPAN></FONT></P>=0A=
<DIV>=0A=
<P><FONT face=3DArial color=3Dnavy size=3D2><SPAN style=3D"FONT-SIZE: =
10pt; COLOR: navy; FONT-FAMILY: Arial">-Josh</SPAN></FONT><FONT =
color=3Dnavy><SPAN style=3D"COLOR: navy"> </SPAN></FONT></P>=0A=
<P><FONT face=3DArial color=3Dnavy size=3D2><SPAN style=3D"FONT-SIZE: =
10pt; COLOR: navy; FONT-FAMILY: Arial">Josh Goldenhar</SPAN></FONT><FONT =
color=3Dnavy><SPAN style=3D"COLOR: navy"> <BR></SPAN></FONT><FONT =
face=3DArial color=3Dnavy size=3D2><SPAN style=3D"FONT-SIZE: 10pt; =
COLOR: navy; FONT-FAMILY: Arial">Phone: 408 963 2408, Cell: 408 547 =
7693</SPAN></FONT><FONT color=3Dnavy><SPAN style=3D"COLOR: navy"> =
</SPAN></FONT></P></DIV>=0A=
<DIV>=0A=
<DIV class=3DMsoNormal style=3D"TEXT-ALIGN: center" align=3Dcenter><FONT =
face=3D"Times New Roman" size=3D3><SPAN style=3D"FONT-SIZE: 12pt">=0A=
<HR tabIndex=3D-1 align=3Dcenter width=3D"100%" SIZE=3D2>=0A=
</SPAN></FONT></DIV>=0A=
<P class=3DMsoNormal><B><FONT face=3DTahoma size=3D2><SPAN =
style=3D"FONT-WEIGHT: bold; FONT-SIZE: 10pt; FONT-FAMILY: =
Tahoma">From:</SPAN></FONT></B><FONT face=3DTahoma size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Tahoma"> Henry Lau <BR><B><SPAN =
style=3D"FONT-WEIGHT: bold">Sent:</SPAN></B> Friday, November 09, 2007 =
11:53 AM<BR><B><SPAN style=3D"FONT-WEIGHT: bold">To:</SPAN></B> Joshua =
Goldenhar; dl-Design Review<BR><B><SPAN style=3D"FONT-WEIGHT: =
bold">Cc:</SPAN></B> Sandrine Boulanger; Vikas Saini; Manohar =
Divate<BR><B><SPAN style=3D"FONT-WEIGHT: bold">Subject:</SPAN></B> RE: =
snapshot autoremove question</SPAN></FONT></P></DIV>=0A=
<P class=3DMsoNormal><FONT face=3D"Times New Roman" size=3D3><SPAN =
style=3D"FONT-SIZE: 12pt"></SPAN></FONT>&nbsp;</P>=0A=
<P class=3DMsoNormal><FONT face=3DArial color=3Dnavy size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">Hi =
Joshua,</SPAN></FONT></P>=0A=
<P class=3DMsoNormal><FONT face=3D"Times New Roman" size=3D3><SPAN =
style=3D"FONT-SIZE: 12pt"></SPAN></FONT>&nbsp;</P>=0A=
<P class=3DMsoNormal><FONT face=3DArial color=3Dnavy size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">Please check =
the best practice section in section 8.1 of the =
doc.&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nb=
sp; </SPAN></FONT></P>=0A=
<P class=3DMsoNormal><FONT face=3D"Times New Roman" size=3D3><SPAN =
style=3D"FONT-SIZE: 12pt"></SPAN></FONT>&nbsp;</P>=0A=
<P class=3DMsoNormal><FONT face=3DArial color=3Dnavy size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: =
Arial">/n/software/FileSystem/snapshot_management_R98_autoremove.doc</SPA=
N></FONT></P>=0A=
<P class=3DMsoNormal><FONT face=3D"Times New Roman" size=3D3><SPAN =
style=3D"FONT-SIZE: 12pt"></SPAN></FONT>&nbsp;</P>=0A=
<P class=3DMsoNormal><FONT face=3DArial color=3Dnavy size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: =
Arial">Thanks,</SPAN></FONT></P>=0A=
<P class=3DMsoNormal><FONT face=3DArial color=3Dnavy size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: =
Arial">Henry</SPAN></FONT></P>=0A=
<P class=3DMsoNormal><FONT face=3D"Times New Roman" size=3D3><SPAN =
style=3D"FONT-SIZE: 12pt"></SPAN></FONT>&nbsp;</P>=0A=
<DIV>=0A=
<DIV class=3DMsoNormal style=3D"TEXT-ALIGN: center" align=3Dcenter><FONT =
face=3D"Times New Roman" size=3D3><SPAN style=3D"FONT-SIZE: 12pt">=0A=
<HR tabIndex=3D-1 align=3Dcenter width=3D"100%" SIZE=3D2>=0A=
</SPAN></FONT></DIV>=0A=
<P class=3DMsoNormal><B><FONT face=3DTahoma size=3D2><SPAN =
style=3D"FONT-WEIGHT: bold; FONT-SIZE: 10pt; FONT-FAMILY: =
Tahoma">From:</SPAN></FONT></B><FONT face=3DTahoma size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Tahoma"> Joshua Goldenhar =
<BR><B><SPAN style=3D"FONT-WEIGHT: bold">Sent:</SPAN></B> Friday, =
November 09, 2007 11:35 AM<BR><B><SPAN style=3D"FONT-WEIGHT: =
bold">To:</SPAN></B> Jobi Ariyamannil; John Keiffer; dl-Design =
Review<BR><B><SPAN style=3D"FONT-WEIGHT: bold">Cc:</SPAN></B> Sandrine =
Boulanger; Vikas Saini; Manohar Divate<BR><B><SPAN style=3D"FONT-WEIGHT: =
bold">Subject:</SPAN></B> RE: snapshot autoremove =
question</SPAN></FONT></P></DIV>=0A=
<P class=3DMsoNormal><FONT face=3D"Times New Roman" size=3D3><SPAN =
style=3D"FONT-SIZE: 12pt"></SPAN></FONT>&nbsp;</P>=0A=
<P class=3DMsoNormal><FONT face=3DArial color=3Dnavy size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">Thanks =
Jobi.</SPAN></FONT></P>=0A=
<P class=3DMsoNormal><FONT face=3D"Times New Roman" size=3D3><SPAN =
style=3D"FONT-SIZE: 12pt"></SPAN></FONT>&nbsp;</P>=0A=
<P class=3DMsoNormal><FONT face=3DArial color=3Dnavy size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">These types =
of questions came up in the last design review and were discussed at =
length.</SPAN></FONT></P>=0A=
<P class=3DMsoNormal><FONT face=3D"Times New Roman" size=3D3><SPAN =
style=3D"FONT-SIZE: 12pt"></SPAN></FONT>&nbsp;</P>=0A=
<P class=3DMsoNormal><FONT face=3DArial color=3Dnavy size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">I think a =
simple rewording of your problem statement can illuminate the overall =
design principle we ended up sticking to:</SPAN></FONT></P>=0A=
<P class=3DMsoNormal><FONT face=3DArial color=3Dnavy size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: =
Arial">&#8220;</SPAN></FONT><FONT face=3DArial size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">I would like to understand =
why we are willing to possibly delete all of a customer&#8217;s =
snapshots, if they have set and reached their autoremoval high water =
mark (ARHWM).&#8221; <FONT color=3D#333399><SPAN style=3D"COLOR: =
#333399">Becomes:</SPAN></FONT> &#8220;&#8230;why is the customer =
willing to possibly delete all of their =
snapshots&#8230;&#8221;</SPAN></FONT></P>=0A=
<P class=3DMsoNormal><FONT face=3D"Times New Roman" size=3D3><SPAN =
style=3D"FONT-SIZE: 12pt"></SPAN></FONT>&nbsp;</P>=0A=
<P class=3DMsoNormal><FONT face=3DArial color=3Dnavy size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">As Jobi =
mentioned, the customer optionally turns this feature on. It&#8217;s our =
job to make sure the documentation and best practices guides issue this =
warning and make operation as clear and understandable as =
possible.</SPAN></FONT></P>=0A=
<P class=3DMsoNormal><FONT face=3D"Times New Roman" size=3D3><SPAN =
style=3D"FONT-SIZE: 12pt"></SPAN></FONT>&nbsp;</P>=0A=
<P class=3DMsoNormal><FONT face=3DArial color=3Dnavy size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">If we come up =
with an arbitrary algorithm to preserve snapshots, there will always be =
a customer that will say &#8220;why did you do it THAT way? &#8211; I =
would rather have had XYZ&#8230;&#8221; </SPAN></FONT></P>=0A=
<P class=3DMsoNormal><FONT face=3D"Times New Roman" size=3D3><SPAN =
style=3D"FONT-SIZE: 12pt"></SPAN></FONT>&nbsp;</P>=0A=
<P class=3DMsoNormal><FONT face=3DArial color=3Dnavy size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">I did not =
know we cannot pin the scheduled snapshots &#8211; I imagine we&#8217;ll =
get an RFE in the future to auto-pin snapshots or set a preservation =
threshold on scheduled snapshots. </SPAN></FONT></P>=0A=
<P class=3DMsoNormal><FONT face=3D"Times New Roman" size=3D3><SPAN =
style=3D"FONT-SIZE: 12pt"></SPAN></FONT>&nbsp;</P>=0A=
<P class=3DMsoNormal><FONT face=3DArial color=3Dnavy size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">For now =
though I really feel the simplicity of the feature as implemented makes =
it easy to understand and makes the &#8220;dangers&#8221; easy to =
understand also.</SPAN></FONT></P>=0A=
<DIV>=0A=
<P><FONT face=3DArial color=3Dnavy size=3D2><SPAN style=3D"FONT-SIZE: =
10pt; COLOR: navy; FONT-FAMILY: Arial">-Josh</SPAN></FONT><FONT =
color=3Dnavy><SPAN style=3D"COLOR: navy"> </SPAN></FONT></P>=0A=
<P><FONT face=3DArial color=3Dnavy size=3D2><SPAN style=3D"FONT-SIZE: =
10pt; COLOR: navy; FONT-FAMILY: Arial">Josh Goldenhar</SPAN></FONT><FONT =
color=3Dnavy><SPAN style=3D"COLOR: navy"> <BR></SPAN></FONT><FONT =
face=3DArial color=3Dnavy size=3D2><SPAN style=3D"FONT-SIZE: 10pt; =
COLOR: navy; FONT-FAMILY: Arial">Phone: 408 963 2408, Cell: 408 547 =
7693</SPAN></FONT><FONT color=3Dnavy><SPAN style=3D"COLOR: navy"> =
</SPAN></FONT></P></DIV>=0A=
<DIV>=0A=
<DIV class=3DMsoNormal style=3D"TEXT-ALIGN: center" align=3Dcenter><FONT =
face=3D"Times New Roman" size=3D3><SPAN style=3D"FONT-SIZE: 12pt">=0A=
<HR tabIndex=3D-1 align=3Dcenter width=3D"100%" SIZE=3D2>=0A=
</SPAN></FONT></DIV>=0A=
<P class=3DMsoNormal><B><FONT face=3DTahoma size=3D2><SPAN =
style=3D"FONT-WEIGHT: bold; FONT-SIZE: 10pt; FONT-FAMILY: =
Tahoma">From:</SPAN></FONT></B><FONT face=3DTahoma size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Tahoma"> Jobi Ariyamannil =
<BR><B><SPAN style=3D"FONT-WEIGHT: bold">Sent:</SPAN></B> Friday, =
November 09, 2007 10:13 AM<BR><B><SPAN style=3D"FONT-WEIGHT: =
bold">To:</SPAN></B> John Keiffer; dl-Design Review<BR><B><SPAN =
style=3D"FONT-WEIGHT: bold">Cc:</SPAN></B> Sandrine Boulanger; Vikas =
Saini; Manohar Divate<BR><B><SPAN style=3D"FONT-WEIGHT: =
bold">Subject:</SPAN></B> RE: snapshot autoremove =
question</SPAN></FONT></P></DIV>=0A=
<P class=3DMsoNormal><FONT face=3D"Times New Roman" size=3D3><SPAN =
style=3D"FONT-SIZE: 12pt"></SPAN></FONT>&nbsp;</P>=0A=
<P class=3DMsoNormal><FONT face=3DArial color=3Dblue size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; COLOR: blue; FONT-FAMILY: Arial">Snapshot auto =
removal is an optional feature somebody needs to turn on.&nbsp; If they =
set the HWM too low, they may end up losing the =
snapshots.</SPAN></FONT></P>=0A=
<P class=3DMsoNormal><FONT face=3DArial color=3Dblue size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; COLOR: blue; FONT-FAMILY: Arial">I don't see =
any need of setting that below 98%.&nbsp; The need for removing =
snapshots automatically is needed when filesystem operates in close to =
full conditions and prevent applications running into ENOSPC because of =
the space pinned by snapshots.&nbsp; By providing an option for the user =
to specify that threshold, we ended up with all these interesting =
possibilities.</SPAN></FONT></P>=0A=
<P class=3DMsoNormal><FONT face=3D"Times New Roman" size=3D3><SPAN =
style=3D"FONT-SIZE: 12pt"></SPAN></FONT>&nbsp;</P>=0A=
<P class=3DMsoNormal><FONT face=3DArial color=3Dblue size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; COLOR: blue; FONT-FAMILY: =
Arial">Regards,</SPAN></FONT></P>=0A=
<P class=3DMsoNormal><FONT face=3DArial color=3Dblue size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; COLOR: blue; FONT-FAMILY: =
Arial">Jobi</SPAN></FONT></P>=0A=
<P class=3DMsoNormal><FONT face=3D"Times New Roman" size=3D3><SPAN =
style=3D"FONT-SIZE: 12pt"></SPAN></FONT>&nbsp;</P>=0A=
<DIV class=3DMsoNormal style=3D"TEXT-ALIGN: center" align=3Dcenter><FONT =
face=3D"Times New Roman" size=3D3><SPAN style=3D"FONT-SIZE: 12pt">=0A=
<HR tabIndex=3D-1 align=3Dcenter width=3D"100%" SIZE=3D2>=0A=
</SPAN></FONT></DIV>=0A=
<P class=3DMsoNormal style=3D"MARGIN-BOTTOM: 12pt"><B><FONT =
face=3DTahoma size=3D2><SPAN style=3D"FONT-WEIGHT: bold; FONT-SIZE: =
10pt; FONT-FAMILY: Tahoma">From:</SPAN></FONT></B><FONT face=3DTahoma =
size=3D2><SPAN style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Tahoma"> John =
Keiffer <BR><B><SPAN style=3D"FONT-WEIGHT: bold">Sent:</SPAN></B> =
Friday, November 09, 2007 10:05 AM<BR><B><SPAN style=3D"FONT-WEIGHT: =
bold">To:</SPAN></B> dl-Design Review<BR><B><SPAN style=3D"FONT-WEIGHT: =
bold">Cc:</SPAN></B> Sandrine Boulanger; Vikas Saini; Manohar =
Divate<BR><B><SPAN style=3D"FONT-WEIGHT: bold">Subject:</SPAN></B> =
snapshot autoremove question</SPAN></FONT></P>=0A=
<P class=3DMsoNormal><FONT face=3DArial color=3Dnavy size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">[opens =
mouth]</SPAN></FONT></P>=0A=
<P class=3DMsoNormal><FONT face=3D"Times New Roman" size=3D3><SPAN =
style=3D"FONT-SIZE: 12pt"></SPAN></FONT>&nbsp;</P>=0A=
<P class=3DMsoNormal><FONT face=3DArial size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">I would like to understand =
why we are willing to possibly delete all of a customer&#8217;s =
snapshots, if they have set and reached their autoremoval high water =
mark (ARHWM). </SPAN></FONT></P>=0A=
<P class=3DMsoNormal><FONT face=3D"Times New Roman" size=3D3><SPAN =
style=3D"FONT-SIZE: 12pt"></SPAN></FONT>&nbsp;</P>=0A=
<P class=3DMsoNormal><FONT face=3DArial size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">It seems that if users in =
the field are keeping a lot of snapshots that this might not be a =
problem, since deleting some might free up the necessary space. If users =
in the field are only scheduling a smaller number of snapshots to be =
taken it is more likely that we might end up deleting them all. =
</SPAN></FONT></P>=0A=
<P class=3DMsoNormal><FONT face=3D"Times New Roman" size=3D3><SPAN =
style=3D"FONT-SIZE: 12pt"></SPAN></FONT>&nbsp;</P>=0A=
<P class=3DMsoNormal style=3D"MARGIN-LEFT: 0.5in"><FONT face=3DArial =
size=3D2><SPAN style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">Example =
problem: I ran it an issue where after creating a large file (using =
pre-allocation), my volume usage was over the ARHWM. I then deleted the =
large file. However, because both the snapshot deletion and file =
deletion happen in the background, the snapshots deletion happened =
before the large file was removed and the volume usage went back down. =
So I ended up losing my file and my snapshots.</SPAN></FONT></P>=0A=
<P class=3DMsoNormal><FONT face=3D"Times New Roman" size=3D3><SPAN =
style=3D"FONT-SIZE: 12pt"></SPAN></FONT>&nbsp;</P>=0A=
<P class=3DMsoNormal><FONT face=3DArial size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">Since we cannot pin =
weekly, daily, or hourly snapshots, and they are likely to be the most =
current, it seems like we should keep at least one. Some of us in QA =
think it might be nice to keep one of each, but at a minimum it seems =
that we should at least keep the most current.<FONT color=3Dnavy><SPAN =
style=3D"COLOR: navy"> </SPAN></FONT>If the last unpinned snapshot needs =
to be deleted in order to free up space, there are bigger issues to deal =
with.</SPAN></FONT></P>=0A=
<P class=3DMsoNormal><FONT face=3D"Times New Roman" size=3D3><SPAN =
style=3D"FONT-SIZE: 12pt"></SPAN></FONT>&nbsp;</P>=0A=
<P class=3DMsoNormal><FONT face=3DArial color=3Dnavy size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">[inserts =
foot]</SPAN></FONT></P>=0A=
<P class=3DMsoNormal><FONT face=3D"Times New Roman" size=3D3><SPAN =
style=3D"FONT-SIZE: 12pt"></SPAN></FONT>&nbsp;</P>=0A=
<P class=3DMsoNormal><FONT face=3DArial size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">Thank =
you,</SPAN></FONT></P>=0A=
<P class=3DMsoNormal><FONT face=3DArial size=3D2><SPAN =
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">John =
Keiffer</SPAN></FONT></P>=0A=
<P class=3DMsoNormal><FONT face=3D"Times New Roman" size=3D3><SPAN =
style=3D"FONT-SIZE: 12pt"></SPAN></FONT>&nbsp;</P>=0A=
<P class=3DMsoNormal><FONT face=3D"Times New Roman" size=3D3><SPAN =
style=3D"FONT-SIZE: =
12pt"></SPAN></FONT>&nbsp;</P></DIV></DIV></DIV></DIV></BODY></HTML>
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