<div dir="ltr">Hi,<div>thanks. A I understand the write process to GPFS filesystem:</div><div><br></div><div>1. Application on a node makes write call</div><div>2. Token Manager stuff is done to coordinate the required-byte-range</div><div>3. mmfsd gets metadata from the file’s metanode</div><div>4. mmfsd acquires a buffer from the page pool</div><div>5. Data is moved from application data buffer to page pool buffer</div><div>6. VSD layer copies data from the page pool to the send pool</div><div> and so on.</div><div><br></div><div>What I am looking at and want to clarify is step 5. Situation when data is moved to page pool. What happen if the server will crash at tjis point?</div><div>Will GPFS use journal to get to stable state?</div><div>Thank you, Pavel<br><div class="gmail_extra"><br clear="all"><div><div class="gmail_signature"><div dir="ltr"><span style="border-collapse:collapse"><font style="color:rgb(51,51,51);font-family:arial,sans-serif;font-size:13px;font-weight:bold"><span style="font-size:small"><div>--</div><div><font style="font-size:13px"><span style="font-size:small">Ing. Pavel Pokorný</span></font></div><div><font face="arial, sans-serif" style="font-weight:normal"><font color="#333333">DATERA s.r.o. </font></font><span style="font-size:13px;font-weight:normal"><span style="color:rgb(255,0,0)">|</span> </span><font face="arial, sans-serif" style="font-weight:normal"><font color="#333333">Ovocný trh 580/2</font></font><font face="arial, sans-serif" style="font-weight:normal"><font color="#333333"> </font></font><span style="font-size:13px;font-weight:normal"><span style="color:rgb(255,0,0)">|</span> Praha</span><font face="arial, sans-serif" style="font-weight:normal"><font color="#333333"> </font></font><span style="font-size:13px;font-weight:normal;color:rgb(255,0,0)">|</span><font face="arial, sans-serif" style="font-weight:normal"> Czech Republic</font></div></span></font></span><div><span style="border-collapse:collapse"><font face="arial, sans-serif" style="color:rgb(51,51,51);font-family:arial,sans-serif"><a href="http://www.datera.cz" target="_blank">www.datera.cz</a> </font><span style="color:rgb(255,0,0);font-family:arial,sans-serif;font-size:13px">|</span><font face="arial, sans-serif" style="color:rgb(51,51,51);font-family:arial,sans-serif"> Mobil: </font><a value="+420602357194" style="color:rgb(51,51,51);font-family:arial,sans-serif;font-size:13px">+420 602 357 194</a><font face="arial, sans-serif" style="color:rgb(51,51,51);font-family:arial,sans-serif"> </font><span style="color:rgb(255,0,0);font-family:arial,sans-serif;font-size:13px">|</span><font face="arial, sans-serif" style="color:rgb(51,51,51);font-family:arial,sans-serif"> E-mail: </font><a href="mailto:pavel.pokorny@datera.cz" style="color:rgb(28,81,168);font-family:arial,sans-serif;font-size:13px" target="_blank">pavel.pokorny@datera.cz</a></span><span style="color:rgb(51,51,51);font-family:arial,sans-serif"> </span></div><div><span style="color:rgb(51,51,51);font-family:arial,sans-serif"><img src="http://ide.datera.cz/logo-datera.jpg"><br></span></div></div></div></div>
<br><div class="gmail_quote">On Sat, Nov 8, 2014 at 1:00 PM, <span dir="ltr"><<a href="mailto:gpfsug-discuss-request@gpfsug.org" target="_blank">gpfsug-discuss-request@gpfsug.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">Send gpfsug-discuss mailing list submissions to<br>
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1. Re: GPFS - pagepool data protection? (Dean Hildebrand)<br>
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Message: 1<br>
Date: Fri, 7 Nov 2014 23:42:06 +0100<br>
From: Dean Hildebrand <<a href="mailto:dhildeb@us.ibm.com">dhildeb@us.ibm.com</a>><br>
To: gpfsug main discussion list <<a href="mailto:gpfsug-discuss@gpfsug.org">gpfsug-discuss@gpfsug.org</a>><br>
Subject: Re: [gpfsug-discuss] GPFS - pagepool data protection?<br>
Message-ID:<br>
<<a href="mailto:OF1ED92A57.DD700837-ONC1257D89.007C4EF1-88257D89.007CB453@us.ibm.com">OF1ED92A57.DD700837-ONC1257D89.007C4EF1-88257D89.007CB453@us.ibm.com</a>><br>
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Hi Paul,<br>
<br>
GPFS correctly implements POSIX semantics and NFS close-to-open semantics.<br>
Its a little complicated, but effectively what this means is that when the<br>
application issues certain calls to ensure data/metadata is "stable" (e.g.,<br>
fsync), then it is guaranteed to be stable. It also controls ordering<br>
between nodes among many other things. As part of making sure data is<br>
stable, the GPFS recovery journal is used in a variety of instances.<br>
<br>
With VMWare ESX using NFS to GPFS, then the same thing occurs, except the<br>
situation is even more simple since every write request will have the<br>
'stable' flag set, ensuring it does writethrough to the storage system.<br>
<br>
Dean Hildebrand<br>
IBM Almaden Research Center<br>
<br>
<br>
<br>
<br>
From: Pavel Pokorny <<a href="mailto:pavel.pokorny@datera.cz">pavel.pokorny@datera.cz</a>><br>
To: <a href="mailto:gpfsug-discuss@gpfsug.org">gpfsug-discuss@gpfsug.org</a><br>
Date: 11/07/2014 03:15 AM<br>
Subject: [gpfsug-discuss] GPFS - pagepool data protection?<br>
Sent by: <a href="mailto:gpfsug-discuss-bounces@gpfsug.org">gpfsug-discuss-bounces@gpfsug.org</a><br>
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<br>
Hello to all,<br>
I would like to ask question about pagepool and protection of data written<br>
through pagepool.<br>
Is there a possibility of loosing data written to GPFS in situation that<br>
data are stored in pagepool but still not written to disks?<br>
I think that for regular file system work this can be solved using GPFS<br>
journal. What about using GPFS as a NFS store for VMware datastores?<br>
Thank you for your answers,<br>
Pavel<br>
--<br>
Ing. Pavel Pokorn?<br>
DATERA s.r.o.?|?Ovocn? trh 580/2?|?Praha?|?Czech Republic<br>
<a href="http://www.datera.cz?|?Mobil:?+420" target="_blank">www.datera.cz?|?Mobil:?+420</a> 602 357 194?|?E-mail:?<a href="mailto:pavel.pokorny@datera.cz">pavel.pokorny@datera.cz</a><br>
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