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<p class="MsoNormal">Why not use a multi-ported direct attached storage (DAS) enclosure? Performance is retained and configuration is straightforward. There are a number of such enclosures available from a range of vendors, many of whom have solutions that
 have been qualified with Lustre.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif";color:#0071C5">Malcolm Cowe<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:8.0pt;font-family:"Arial","sans-serif"">High Performance Data Division<o:p></o:p></span></p>
<p class="MsoNormal"><b><span lang="EN-US" style="font-size:8.0pt;font-family:"Arial","sans-serif"">Intel Corporation</span></b><span lang="EN-US" style="font-size:8.0pt;font-family:"Arial","sans-serif""> |
<span style="color:#0071C5">www.intel.com</span><o:p></o:p></span></p>
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<p class="MsoNormal" style="margin-left:36.0pt"><a name="_____replyseparator"></a><b><span lang="EN-US" style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span lang="EN-US" style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">
 lustre-discuss [mailto:lustre-discuss-bounces@lists.lustre.org] <b>On Behalf Of </b>
jeevan.patnaik@wipro.com<br>
<b>Sent:</b> Monday, March 14, 2016 11:37 PM<br>
<b>To:</b> lustre-discuss@lists.lustre.org<br>
<b>Subject:</b> [lustre-discuss] Lustre failover configuration - Need help in selecting storage<o:p></o:p></span></p>
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<p style="mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:12.0pt;margin-left:0cm">
<span style="font-size:11.5pt;font-family:"Arial","sans-serif";color:#222426">We need storage specifically for HPC Lustre failover setup, where it is must that two servers should share same block level storage to have failover configuration.<o:p></o:p></span></p>
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<span style="font-size:11.5pt;font-family:"Arial","sans-serif";color:#222426">With very limited knowledge on hardware, I have the below understanding:<o:p></o:p></span></p>
<p class="MsoNormal" style="mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:6.0pt;margin-left:22.5pt;text-indent:-18.0pt">
<span style="font-size:10.0pt;font-family:Symbol;color:#222426"></span><span style="font-size:7.0pt;font-family:"Times New Roman","serif";color:#222426">        
</span><span style="font-size:11.5pt;font-family:"Arial","sans-serif";color:#222426">NAS can be used for shared storage, but there will be bottleneck for speed due to intermediate network.<o:p></o:p></span></p>
<p class="MsoNormal" style="mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:6.0pt;margin-left:22.5pt;text-indent:-18.0pt">
<span style="font-size:10.0pt;font-family:Symbol;color:#222426"></span><span style="font-size:7.0pt;font-family:"Times New Roman","serif";color:#222426">        
</span><span style="font-size:11.5pt;font-family:"Arial","sans-serif";color:#222426">SAN can be used, but it is costly to implement the solution and not really needed for Storage of 50-100TB.<o:p></o:p></span></p>
<p class="MsoNormal" style="mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:6.0pt;margin-left:22.5pt;text-indent:-18.0pt">
<span style="font-size:10.0pt;font-family:Symbol;color:#222426"></span><span style="font-size:7.0pt;font-family:"Times New Roman","serif";color:#222426">        
</span><span style="font-size:11.5pt;font-family:"Arial","sans-serif";color:#222426">If at all we find multiple iscsi ports to the storage enclosure, the storage can be used only by splitting i.e., works as two storage devices and the same storage can't be
 used by both the<br>
systems. (And one thing to remind here, in the lustre setup, both the servers would be only attached, but only one will be used (not sure, how it is possible, again need to check on this).<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:22.5pt;text-indent:-18.0pt"><span style="font-size:10.0pt;font-family:Symbol;color:#222426"></span><span style="font-size:7.0pt;font-family:"Times New Roman","serif";color:#222426">        
</span><span style="font-size:11.5pt;font-family:"Arial","sans-serif";color:#222426">Having two virtual machines may be how we can do it. But, then, it is not really helpful for the purpose of failover, as the physical machine would be only one.<o:p></o:p></span></p>
<p style="mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:12.0pt;margin-left:0cm">
<span style="font-size:11.5pt;font-family:"Arial","sans-serif";color:#222426">But, while posting the question, I am thinking, maybe we can compromise on speed in NAS, if we try having one directly attached server (primary) and the other attached via network
 (failover), so we face slowness only when the primary stops working.<o:p></o:p></span></p>
<p style="mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:12.0pt;margin-left:0cm">
<span style="font-size:11.5pt;font-family:"Arial","sans-serif";color:#222426">As I posted the similar question on Server Fault:
<a href="http://serverfault.com/questions/763569/is-it-possible-to-have-a-directly-attached-shared-storage-accessed-at-block-lev">
http://serverfault.com/questions/763569/is-it-possible-to-have-a-directly-attached-shared-storage-accessed-at-block-lev</a>, I have got the following response:</span><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:#222426;border:none windowtext 1.0pt;padding:0cm"><br>
<span class="comment-copy">“Have you actually attempted to set up a proof of concept, or at least looked through the</span><span class="apple-converted-space"> </span><span class="comment-copy"><a href="http://doc.lustre.org/lustre_manual.xhtml"><span style="color:#005999">documentation</span></a>?
 Lustre really doesn't care very much how you connect to the underlying storage, so you can do whatever gets you the bandwidth you need.”</span></span><span class="comment-copy"><span style="font-size:10.0pt;border:none windowtext 1.0pt;padding:0cm"><o:p></o:p></span></span></p>
<p style="mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:12.0pt;margin-left:0cm">
<span class="comment-copy"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:#222426;border:none windowtext 1.0pt;padding:0cm">So, is it true that we don’t need to worry about bandwidth of the storage server?<o:p></o:p></span></span></p>
<p style="mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:12.0pt;margin-left:0cm">
<span class="comment-copy"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:#222426;border:none windowtext 1.0pt;padding:0cm">I mean, for example: the communication as I understood is as follows:<o:p></o:p></span></span></p>
<p style="mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:12.0pt;margin-left:36.0pt;text-indent:-18.0pt">
<span class="comment-copy"><span style="font-size:10.0pt;font-family:Wingdings;color:#222426"></span></span><span class="comment-copy"><span style="font-size:7.0pt;color:#222426"> 
</span></span><span class="comment-copy"><span style="font-size:10.0pt;border:none windowtext 1.0pt;padding:0cm">Client
</span></span><span class="comment-copy"><span style="font-size:10.0pt;font-family:Wingdings;border:none windowtext 1.0pt;padding:0cm"></span></span><span class="comment-copy"><span style="font-size:10.0pt;border:none windowtext 1.0pt;padding:0cm"> MGS (Ethernet)</span></span><span class="comment-copy"><span style="font-size:11.5pt;font-family:"Arial","sans-serif";color:#222426"><o:p></o:p></span></span></p>
<p style="mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:12.0pt;margin-left:36.0pt;text-indent:-18.0pt">
<span class="comment-copy"><span style="font-size:10.0pt;font-family:Wingdings;color:#222426"></span></span><span class="comment-copy"><span style="font-size:7.0pt;color:#222426"> 
</span></span><span class="comment-copy"><span style="font-size:10.0pt;border:none windowtext 1.0pt;padding:0cm">MGS
</span></span><span class="comment-copy"><span style="font-size:10.0pt;font-family:Wingdings;border:none windowtext 1.0pt;padding:0cm"></span></span><span class="comment-copy"><span style="font-size:10.0pt;border:none windowtext 1.0pt;padding:0cm"> MGT (Direct/ISCSI)
</span></span><span class="comment-copy"><span style="font-size:11.5pt;font-family:"Arial","sans-serif";color:#222426"><o:p></o:p></span></span></p>
<p style="mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:12.0pt;margin-left:36.0pt;text-indent:-18.0pt">
<span class="comment-copy"><span style="font-size:10.0pt;font-family:Wingdings;color:#222426"></span></span><span class="comment-copy"><span style="font-size:7.0pt;color:#222426"> 
</span></span><span class="comment-copy"><span style="font-size:10.0pt;border:none windowtext 1.0pt;padding:0cm">MGS
</span></span><span class="comment-copy"><span style="font-size:10.0pt;font-family:Wingdings;border:none windowtext 1.0pt;padding:0cm"></span></span><span class="comment-copy"><span style="font-size:10.0pt;border:none windowtext 1.0pt;padding:0cm"> MDS (Ethernet/Internal
 Communication)</span></span><span class="comment-copy"><span style="font-size:11.5pt;font-family:"Arial","sans-serif";color:#222426"><o:p></o:p></span></span></p>
<p style="mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:12.0pt;margin-left:36.0pt;text-indent:-18.0pt">
<span class="comment-copy"><span style="font-size:10.0pt;font-family:Wingdings;color:#222426"></span></span><span class="comment-copy"><span style="font-size:7.0pt;color:#222426"> 
</span></span><span class="comment-copy"><span style="font-size:10.0pt;border:none windowtext 1.0pt;padding:0cm">MDS
</span></span><span class="comment-copy"><span style="font-size:10.0pt;font-family:Wingdings;border:none windowtext 1.0pt;padding:0cm"></span></span><span class="comment-copy"><span style="font-size:10.0pt;border:none windowtext 1.0pt;padding:0cm"> MDT (Direct/ISCSI/Ethernet)</span></span><span class="comment-copy"><span style="font-size:11.5pt;font-family:"Arial","sans-serif";color:#222426"><o:p></o:p></span></span></p>
<p style="mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:12.0pt;margin-left:36.0pt;text-indent:-18.0pt">
<span class="comment-copy"><span style="font-size:10.0pt;font-family:Wingdings;color:#222426"></span></span><span class="comment-copy"><span style="font-size:7.0pt;color:#222426"> 
</span></span><span class="comment-copy"><span style="font-size:10.0pt;border:none windowtext 1.0pt;padding:0cm">MDS
</span></span><span class="comment-copy"><span style="font-size:10.0pt;font-family:Wingdings;border:none windowtext 1.0pt;padding:0cm"></span></span><span class="comment-copy"><span style="font-size:10.0pt;border:none windowtext 1.0pt;padding:0cm"> OSS (Ethernet)</span></span><span class="comment-copy"><span style="font-size:11.5pt;font-family:"Arial","sans-serif";color:#222426"><o:p></o:p></span></span></p>
<p style="mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:12.0pt;margin-left:36.0pt;text-indent:-18.0pt">
<span class="comment-copy"><span style="font-size:10.0pt;font-family:Wingdings;color:#222426"></span></span><span class="comment-copy"><span style="font-size:7.0pt;color:#222426"> 
</span></span><span class="comment-copy"><span style="font-size:10.0pt;border:none windowtext 1.0pt;padding:0cm">OSS
</span></span><span class="comment-copy"><span style="font-size:10.0pt;font-family:Wingdings;border:none windowtext 1.0pt;padding:0cm"></span></span><span class="comment-copy"><span style="font-size:10.0pt;border:none windowtext 1.0pt;padding:0cm"> OST (Direct/ISCSI/Ethernet)
</span></span><span class="comment-copy"><span style="font-size:11.5pt;font-family:"Arial","sans-serif";color:#222426"><o:p></o:p></span></span></p>
<p style="mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:12.0pt;margin-left:36.0pt;text-indent:-18.0pt">
<span style="font-size:10.0pt;font-family:Wingdings;color:#222426"></span><span style="font-size:7.0pt;color:#222426"> 
</span><span class="comment-copy"><span style="font-size:10.0pt;border:none windowtext 1.0pt;padding:0cm">OST
</span></span><span class="comment-copy"><span style="font-size:10.0pt;font-family:Wingdings;border:none windowtext 1.0pt;padding:0cm"></span></span><span class="comment-copy"><span style="font-size:10.0pt;border:none windowtext 1.0pt;padding:0cm"> Client
 (Ethernet) </span></span><o:p></o:p></p>
<p style="mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:12.0pt;margin-left:0cm">
<span style="font-size:11.5pt;font-family:"Arial","sans-serif";color:#222426">Does it mean that, the performance won’t be affected at any stage, if iscsi is replaced by Ethernet or by using limited bandwidth?
<o:p></o:p></span></p>
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</v:shape><![endif]--><![if !vml]><span style="mso-ignore:vglayout;position:absolute;z-index:251657726;left:0px;margin-left:356px;margin-top:12px;width:79px;height:79px"><img width="79" height="79" src="cid:image003.jpg@01D17E8C.4A897A60" alt="WNC_Logo" v:shapes="Picture_x0020_1"></span><![endif]><span lang="EN-US"><b><span style="color:#2E74B5">--<o:p></o:p></span></b></span></p>
<p class="MsoNormal" style="margin-left:36.0pt"><b><span lang="EN-US" style="font-size:10.0pt;color:#2E74B5">Thanks and Regards,<o:p></o:p></span></b></p>
<p class="MsoNormal" style="margin-left:36.0pt"><b><span lang="EN-US" style="color:#C45911">Jeevan Patnaik B</span></b><b><span lang="EN-US" style="color:#2E74B5">
</span></b><span lang="EN-US" style="color:#2E74B5">| </span><span lang="EN-US" style="color:#BF8F00">Project Engineer</span><span lang="EN-US" style="color:#2E74B5">
<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:36.0pt"><span lang="EN-US" style="color:#002060">Nokia IT - HEE Platform</span><span lang="EN-US" style="color:#2E74B5"> |
</span><span lang="EN-US" style="color:#2F5496">WIPRO Technologies - Hyderabad</span><span lang="EN-US" style="color:#2E74B5"><o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:36.0pt"><span lang="EN-US" style="color:#7F7F7F">Mob: +91-9000607181</span><span lang="EN-US" style="color:#2E74B5">
</span><span lang="EN-US" style="color:#7F7F7F">| Off: +91-4030970347.</span><span lang="EN-US" style="color:black">
</span><span lang="EN-US" style="color:#2E74B5"><o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:36.0pt"><span lang="EN-US"><o:p> </o:p></span></p>
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