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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Hi Bruno,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">I’ll respond to the questions inline.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-ligatures:standard">Peter J. Pouliot, CISSP<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-ligatures:standard">Senior SDET, OpenStack<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-ligatures:standard"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-ligatures:standard">Microsoft
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-ligatures:standard">New England Research & Development Center<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-ligatures:standard">One Memorial Drive,Cambridge, MA 02142<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-ligatures:standard"><a href="mailto:PPOULIOT@microsoft.com">PPOULIOT@microsoft.com</a> | Tel: +1(857) 453 6436<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif"">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif""> Bruno Oliveira ~lychinus [mailto:brunnop.oliveira@gmail.com]
<br>
<b>Sent:</b> Wednesday, June 26, 2013 10:00 AM<br>
<b>To:</b> Peter Pouliot<br>
<b>Subject:</b> [Openstack][Cinder][Hyper-V] iSCSI dealing in a High-Throughput Network<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><span style="font-family:"Arial","sans-serif";color:#444444">Hello Peter, how are you doing? <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Arial","sans-serif";color:#444444"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Arial","sans-serif";color:#444444">Excuse-me for the sudden email, but there's something very very important that I'd like to ask your advice for, if you don't mind.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Arial","sans-serif";color:#444444"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Arial","sans-serif";color:#444444">We're (at MANDIC) are now dealing with what would be the best protocol for when dealing with Cinder (Block Storage): NFS or iSCSI. <o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">ISCSI is the best option.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Arial","sans-serif";color:#444444"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Arial","sans-serif";color:#444444">As far as I've read, iSCSI is extremely resilient and more reliable than NFS since it already address issues like network faults, by using multiple channels as individual paths
to make sure the data reaches its targets. On the other hand, NFS would require the infrastructure itself to guarantee the network connectivity.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">NFS exports a filesystem and require a nfs client at the OS layer.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">ISCSI can be consume directly via hardware and exports block devices.
<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Arial","sans-serif";color:#444444"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Arial","sans-serif";color:#444444">That for a production use is very important indeed, but I cannot forget of the performance between the two (I've also got to know that NFS might have a superior read IO, due to
its read_cache, but it lacks when it comes to writing -- unless I have some sort of write cache, like the one deployed in the ZFS filesystem). <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Arial","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">So once again it depends on how you want to use it. NFS requires some sort of distributed filesystem under it to scale.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Currently with ISCSI we just just plug in storage nodes, and don’t care about filesystems.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Arial","sans-serif";color:#444444">Note: we have a Sun/Oracle Storage using the ZFS filesystem for what we're using currently.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Arial","sans-serif";color:#444444"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span style="font-family:"Arial","sans-serif";color:#444444">Question 1)
</span></b><span style="font-family:"Arial","sans-serif";color:#444444">In any case, I'd like to know your thoughts on it. I'm not sure myself if it would be somewhat possible to have Hyper-V (even 2012) using a NFS, is it possible at all ?<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">So Hyper-V itself uses the native ISCSI client. (You need to start the iscsi initiator service).<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">And that’s it. It can by default pass cinder iscsi volumes.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">In terms of comsuming NFS, there is also a native nfs client. That is a feature that must be installed, and I’m not entirely sure if it’s present or available
on hyper-v server. You may need to use a full server sku for that.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Now that being said in theory work could be done to have the cinder client work natively as long as that feature is present however currently it only supports
iscsi.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Arial","sans-serif";color:#444444"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span style="font-family:"Arial","sans-serif";color:#444444">Question 2)
</span></b><span style="font-family:"Arial","sans-serif";color:#444444">Performance-wise, in a very high-throughput network (supposely 10G), would iSCSI perform better than other alternatives ? (I've read a lot on the internet, but as you know, I'm not sure
how practical these articles can be or if they're just comparing them theorically) <o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">I personally ran ISCSI for years over 1G with out incident for production workloads with linux clusters.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">That being said, we still did dedicate interfaces for storage traffic.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Arial","sans-serif";color:#444444"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Arial","sans-serif";color:#444444">Thank you very much, Peter.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Arial","sans-serif";color:#444444"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Arial","sans-serif";color:#444444">Best regards.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Arial","sans-serif";color:#444444"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Arial","sans-serif";color:#444444">--</span><o:p></o:p></p>
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<p class="MsoNormal"><b><span style="font-family:"Arial","sans-serif";color:#444444"><o:p> </o:p></span></b></p>
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<p class="MsoNormal"><b><span style="font-family:"Arial","sans-serif";color:#444444"><o:p></o:p></span></b></p>
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<p class="MsoNormal"><b><span style="font-family:"Arial","sans-serif";color:#333333">Bruno Oliveira</span></b><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-size:7.5pt;font-family:"Arial","sans-serif";color:#444444">Developer, Software Engineer<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:#444444">irc: lychinus | skype: brunnop.oliveira</span><o:p></o:p></p>
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<p class="MsoNormal"><a href="mailto:brunnop.oliveira@gmail.com" target="_blank"><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">brunnop.oliveira@gmail.com</span></a><o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><a href="http://br.linkedin.com/in/brunnopoliveira" target="_blank"><span style="text-decoration:none"><img border="0" id="_x0000_i1025" src="https://drive.google.com/uc?export=view&id=0B2UQ5KHL27SYR1B0UVJUOWs4dmc"></span></a> <a href="http://twitter.com/lychinus" target="_blank"><span style="text-decoration:none"><img border="0" id="_x0000_i1026" src="https://drive.google.com/uc?export=view&id=0B2UQ5KHL27SYYWxKTlU4ZlBueGc"></span></a> <a href="http://gplus.to/lychinus" target="_blank"><span style="text-decoration:none"><img border="0" id="_x0000_i1027" src="https://drive.google.com/uc?export=view&id=0B2UQ5KHL27SYWUhoeTg2b3FaZDg"></span></a> <o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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