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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Thanks. This approach looks promising.<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:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> Alex Glikson [mailto:GLIKSON@il.ibm.com] <br><b>Sent:</b> Saturday, June 01, 2013 2:18 AM<br><b>To:</b> openstack@lists.launchpad.net; chris@christopherbartels.com<br><b>Subject:</b> Re: [Openstack] VM disk affinity during live migration<o:p></o:p></span></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Right. A slightly different approach (requiring admin effort) would be to define two host aggregates -- one reporting SSD as one of the capabilities of its hosts, and another one reporting SAS. Then the admin can attach the corresponding capability as a an extra spec of an instance flavor, and use Filter Scheduler with AggregateInstanceExtraSpecsFilter to make sure instances would not be placed on a hosts which belong to a wrong aggregate. All this can be done already (see </span><a href="http://docs.openstack.org/trunk/openstack-compute/admin/content/host-aggregates.html">http://docs.openstack.org/trunk/openstack-compute/admin/content/host-aggregates.html</a><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>). The missing piece (which is, I believe, going to be resolved in Havana) would be to prevent admin from live-migrating an instance to a wrong location manually (but this wouldn't be an issue if the admin live-migrates without explicitly specifying destination, as Jay pointed out).</span> <br><br><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Regards,</span> <br><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Alex</span> <br><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'><br></span><br><br><br><span style='font-size:7.5pt;font-family:"Arial","sans-serif";color:#5F5F5F'>From: </span><span style='font-size:7.5pt;font-family:"Arial","sans-serif"'>Lau Jay <<a href="mailto:jay.lau.513@gmail.com">jay.lau.513@gmail.com</a>></span> <br><span style='font-size:7.5pt;font-family:"Arial","sans-serif";color:#5F5F5F'>To: </span><span style='font-size:7.5pt;font-family:"Arial","sans-serif"'><a href="mailto:chris@christopherbartels.com">chris@christopherbartels.com</a>, </span><br><span style='font-size:7.5pt;font-family:"Arial","sans-serif";color:#5F5F5F'>Cc: </span><span style='font-size:7.5pt;font-family:"Arial","sans-serif"'>Alex Glikson/Haifa/IBM@IBMIL, <a href="mailto:openstack@lists.launchpad.net">openstack@lists.launchpad.net</a></span> <br><span style='font-size:7.5pt;font-family:"Arial","sans-serif";color:#5F5F5F'>Date: </span><span style='font-size:7.5pt;font-family:"Arial","sans-serif"'>01/06/2013 07:39 AM</span> <br><span style='font-size:7.5pt;font-family:"Arial","sans-serif";color:#5F5F5F'>Subject: </span><span style='font-size:7.5pt;font-family:"Arial","sans-serif"'>Re: [Openstack] VM disk affinity during live migration</span> <o:p></o:p></p><div class=MsoNormal align=center style='text-align:center'><hr size=2 width="100%" noshade style='color:gray' align=center></div><p class=MsoNormal><br><br><br>Hi Chris, <br><br>I think that you are using live migration without specifying target host, right? OpenStack cannot handle your case for now, but it has very flexible framework to enable you DIY your migration logic.<br><br>1) Make sure SSD or SAS can be reported by nova compute, you might want to update nova compute driver to report those metrics? <br>2) Add a new scheduler filter to do your logic checking for SSD and SAS.<br><br>Thanks,<br><br>Jay<br><br><br><br>2013/6/1 Chris Bartels <<a href="mailto:chris@christopherbartels.com" target="_blank">chris@christopherbartels.com</a>> <br><span style='font-size:10.0pt;font-family:"Calibri","sans-serif";color:#004080'>Thanks for your reply.</span> <o:p></o:p></p><p><span style='font-size:10.0pt;font-family:"Calibri","sans-serif";color:#004080'> </span> <o:p></o:p></p><p><span style='font-size:10.0pt;font-family:"Calibri","sans-serif";color:#004080'>Your reply implies that its possible to ensure that the disks stay on the right target manually. What would you have to do to make sure this happened?</span> <o:p></o:p></p><p><span style='font-size:10.0pt;font-family:"Calibri","sans-serif";color:#004080'> </span> <o:p></o:p></p><p><span style='font-size:10.0pt;font-family:"Calibri","sans-serif";color:#004080'>The SAS space is 228GB & the SSD space is only 64GB.</span> <o:p></o:p></p><p><span style='font-size:10.0pt;font-family:"Calibri","sans-serif";color:#004080'> </span> <o:p></o:p></p><p><span style='font-size:10.0pt;font-family:"Calibri","sans-serif";color:#004080'>So the SAS disk image wouldn’t fit on the SSD, but the SSD image would fit on the SAS, so the migration system I imagine wouldn’t be able to screw it up since it would have to keep the large SAS image on the SAS target, and would then only be able to place the smaller SSD image on the SSD.</span> <o:p></o:p></p><p><span style='font-size:10.0pt;font-family:"Calibri","sans-serif";color:#004080'> </span> <o:p></o:p></p><p><span style='font-size:10.0pt;font-family:"Calibri","sans-serif";color:#004080'>But you say it’s a work in progress so that could mean anything could happen.</span> <o:p></o:p></p><p><span style='font-size:10.0pt;font-family:"Calibri","sans-serif";color:#004080'> </span> <o:p></o:p></p><p><span style='font-size:10.0pt;font-family:"Calibri","sans-serif";color:#004080'>What does the actual process look like when I would migrate a VM from one server to another? What exactly would I have to do to make sure it went right?</span> <o:p></o:p></p><p><span style='font-size:10.0pt;font-family:"Calibri","sans-serif";color:#004080'> </span> <o:p></o:p></p><p><span style='font-size:10.0pt;font-family:"Calibri","sans-serif";color:#004080'>Thanks.</span> <o:p></o:p></p><p><span style='font-size:10.0pt;font-family:"Calibri","sans-serif";color:#004080'> </span> <o:p></o:p></p><p><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> Alex Glikson [mailto:</span><a href="mailto:GLIKSON@il.ibm.com" target="_blank"><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>GLIKSON@il.ibm.com</span></a><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>] <b><br>Sent:</b> Friday, May 31, 2013 7:34 AM<b><br>To:</b> </span><a href="mailto:chris@christopherbartels.com" target="_blank"><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>chris@christopherbartels.com</span></a><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'><br>Cc:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> </span><a href="mailto:openstack@lists.launchpad.net" target="_blank"><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>openstack@lists.launchpad.net</span></a><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'><br>Subject:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> Re: [Openstack] VM disk affinity during live migration</span> <o:p></o:p></p><p> <o:p></o:p></p><p><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>There is an ongoing work to refactor live migration code, including use of scheduler to find/validate placement. At the moment the admin would need to make sure he/she is doing the right thing.</span> <br><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'><br>Regards,</span> <span style='font-size:10.0pt;font-family:"Arial","sans-serif"'><br>Alex</span> <span style='font-size:10.0pt;font-family:"Arial","sans-serif"'><br><br></span><br><span style='font-size:7.5pt;font-family:"Arial","sans-serif";color:#5F5F5F'><br>From: </span><span style='font-size:7.5pt;font-family:"Arial","sans-serif"'>"Chris Bartels" <</span><a href="mailto:chris@christopherbartels.com" target="_blank"><span style='font-size:7.5pt;font-family:"Arial","sans-serif"'>chris@christopherbartels.com</span></a><span style='font-size:7.5pt;font-family:"Arial","sans-serif"'>></span> <span style='font-size:7.5pt;font-family:"Arial","sans-serif";color:#5F5F5F'><br>To: </span><span style='font-size:7.5pt;font-family:"Arial","sans-serif"'><</span><a href="mailto:openstack@lists.launchpad.net" target="_blank"><span style='font-size:7.5pt;font-family:"Arial","sans-serif"'>openstack@lists.launchpad.net</span></a><span style='font-size:7.5pt;font-family:"Arial","sans-serif"'>>, <span style='color:#5F5F5F'><br>Date: </span>31/05/2013 02:12 PM</span> <span style='font-size:7.5pt;font-family:"Arial","sans-serif";color:#5F5F5F'><br>Subject: </span><span style='font-size:7.5pt;font-family:"Arial","sans-serif"'>[Openstack] VM disk affinity during live migration</span> <span style='font-size:7.5pt;font-family:"Arial","sans-serif";color:#5F5F5F'><br>Sent by: </span><span style='font-size:7.5pt;font-family:"Arial","sans-serif"'>"Openstack" <</span><a href="mailto:openstack-bounces+glikson=il.ibm.com@lists.launchpad.net" target="_blank"><span style='font-size:7.5pt;font-family:"Arial","sans-serif"'>openstack-bounces+glikson=il.ibm.com@lists.launchpad.net</span></a><span style='font-size:7.5pt;font-family:"Arial","sans-serif"'>></span> <o:p></o:p></p><div class=MsoNormal align=center style='text-align:center'><hr size=2 width="100%" noshade style='color:gray' align=center></div><p style='margin-bottom:12.0pt'><br><br><span style='font-size:10.0pt;font-family:"Calibri","sans-serif"'><br>Hi,</span> <span style='font-size:10.0pt;font-family:"Calibri","sans-serif"'><br> </span> <span style='font-size:10.0pt;font-family:"Calibri","sans-serif"'><br>Please forgive me if I’ve asked already here on the list- I didn’t get a reply & I really need an answer, so I’m asking again in simpler terms this time.</span> <span style='font-size:10.0pt;font-family:"Calibri","sans-serif"'><br> </span> <span style='font-size:10.0pt;font-family:"Calibri","sans-serif"'><br>If I have a cluster of servers, each with spindle drives & SSDs, how can I be sure VM disks which reside on spindle drives migrate to spindle drives & those which reside on SSDs stay on SSDs as they migrate between servers?</span> <span style='font-size:10.0pt;font-family:"Calibri","sans-serif"'><br> </span> <span style='font-size:10.0pt;font-family:"Calibri","sans-serif"'><br>Thanks,</span> <span style='font-size:10.0pt;font-family:"Calibri","sans-serif"'><br>Chris</span><tt><span style='font-size:10.0pt'>_______________________________________________</span></tt><span style='font-size:10.0pt;font-family:"Courier New"'><br>Mailing list: </span><a href="https://launchpad.net/~openstack" target="_blank"><tt><span style='font-size:10.0pt'>https://launchpad.net/~openstack</span></tt></a><span style='font-size:10.0pt;font-family:"Courier New"'><br>Post to : </span><a href="mailto:openstack@lists.launchpad.net" target="_blank"><span style='font-size:10.0pt;font-family:"Courier New"'>openstack@lists.launchpad.net</span></a><span style='font-size:10.0pt;font-family:"Courier New"'><br>Unsubscribe : </span><a href="https://launchpad.net/~openstack" target="_blank"><tt><span style='font-size:10.0pt'>https://launchpad.net/~openstack</span></tt></a><span style='font-size:10.0pt;font-family:"Courier New"'><br>More help : </span><a href="https://help.launchpad.net/ListHelp" target="_blank"><tt><span style='font-size:10.0pt'>https://help.launchpad.net/ListHelp</span></tt></a> <br><br>_______________________________________________<br>Mailing list: <a href="https://launchpad.net/~openstack" target="_blank">https://launchpad.net/~openstack</a><br>Post to : <a href="mailto:openstack@lists.launchpad.net">openstack@lists.launchpad.net</a><br>Unsubscribe : <a href="https://launchpad.net/~openstack" target="_blank">https://launchpad.net/~openstack</a><br>More help : <a href="https://help.launchpad.net/ListHelp" target="_blank">https://help.launchpad.net/ListHelp</a><br><br><o:p></o:p></p></div></body></html>