<div dir="ltr"><div><div>Cool, Alex! I think that this is the best way for Chris.<br><br></div>Thanks,<br><br></div>Jay<br><br></div><div class="gmail_extra"><br><br><div class="gmail_quote">2013/6/1 Alex Glikson <span dir="ltr"><<a href="mailto:GLIKSON@il.ibm.com" target="_blank">GLIKSON@il.ibm.com</a>></span><br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><font face="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 </font><a href="http://docs.openstack.org/trunk/openstack-compute/admin/content/host-aggregates.html" target="_blank"><font color="blue" size="3"><u>http://docs.openstack.org/trunk/openstack-compute/admin/content/host-aggregates.html</u></font></a><font face="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).</font>
<br>
<br><font face="sans-serif">Regards,</font>
<br><font face="sans-serif">Alex</font>
<br><font face="sans-serif"><br>
</font>
<br>
<br>
<br><font color="#5f5f5f" face="sans-serif" size="1">From:
</font><font face="sans-serif" size="1">Lau Jay <<a href="mailto:jay.lau.513@gmail.com" target="_blank">jay.lau.513@gmail.com</a>></font>
<br><font color="#5f5f5f" face="sans-serif" size="1">To:
</font><font face="sans-serif" size="1"><a href="mailto:chris@christopherbartels.com" target="_blank">chris@christopherbartels.com</a>,
</font>
<br><font color="#5f5f5f" face="sans-serif" size="1">Cc:
</font><font face="sans-serif" size="1">Alex Glikson/Haifa/IBM@IBMIL,
<a href="mailto:openstack@lists.launchpad.net" target="_blank">openstack@lists.launchpad.net</a></font>
<br><font color="#5f5f5f" face="sans-serif" size="1">Date:
</font><font face="sans-serif" size="1">01/06/2013 07:39 AM</font>
<br><div class="im"><font color="#5f5f5f" face="sans-serif" size="1">Subject:
</font><font face="sans-serif" size="1">Re: [Openstack]
VM disk affinity during live migration</font>
<br>
</div><hr noshade><div class="im">
<br>
<br>
<br><font size="3">Hi Chris,</font>
<br><font size="3"><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>
</font>
<br><font size="3">1) Make sure SSD or SAS can be reported by nova compute,
you might want to update nova compute driver to report those metrics?</font>
<br><font size="3">2) Add a new scheduler filter to do your logic checking
for SSD and SAS.<br>
</font>
<br><font size="3">Thanks,<br>
</font>
<br><font size="3">Jay<br>
</font>
<br><font size="3"><br>
</font>
<br><font size="3">2013/6/1 Chris Bartels <</font><a href="mailto:chris@christopherbartels.com" target="_blank"><font color="blue" size="3"><u>chris@christopherbartels.com</u></font></a><font size="3">></font>
<br><font color="#004080" face="Calibri">Thanks for your reply.</font>
</div><p><font color="#004080" face="Calibri"> </font>
</p><p></p><div class="im"><font color="#004080" face="Calibri">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?</font>
</div><p><font color="#004080" face="Calibri"> </font>
</p><p></p><div class="im"><font color="#004080" face="Calibri">The SAS space is 228GB &
the SSD space is only 64GB.</font>
</div><p><font color="#004080" face="Calibri"> </font>
</p><p></p><div class="im"><font color="#004080" face="Calibri">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.</font>
</div><p><font color="#004080" face="Calibri"> </font>
</p><p></p><div class="im"><font color="#004080" face="Calibri">But you say it’s a work in
progress so that could mean anything could happen.</font>
</div><p><font color="#004080" face="Calibri"> </font>
</p><p></p><div class="im"><font color="#004080" face="Calibri">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?</font>
</div><p><font color="#004080" face="Calibri"> </font>
</p><p><font color="#004080" face="Calibri">Thanks.</font>
</p><p><font color="#004080" face="Calibri"> </font>
</p><p></p><div class="im"><font face="Tahoma"><b>From:</b> Alex Glikson [mailto:</font><a href="mailto:GLIKSON@il.ibm.com" target="_blank"><font color="blue" face="Tahoma"><u>GLIKSON@il.ibm.com</u></font></a><font face="Tahoma">]
<b><br>
Sent:</b> Friday, May 31, 2013 7:34 AM<b><br>
To:</b> </font><a href="mailto:chris@christopherbartels.com" target="_blank"><font color="blue" face="Tahoma"><u>chris@christopherbartels.com</u></font></a><font face="Tahoma"><b><br>
Cc:</b> </font><a href="mailto:openstack@lists.launchpad.net" target="_blank"><font color="blue" face="Tahoma"><u>openstack@lists.launchpad.net</u></font></a><font face="Tahoma"><b><br>
Subject:</b> Re: [Openstack] VM disk affinity during live migration</font>
</div><p><font size="3"> </font>
</p><p></p><div class="im"><font face="Arial">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.</font><font size="3"> <br>
</font><font face="Arial"><br>
Regards,</font><font size="3"> </font><font face="Arial"><br>
Alex</font><font size="3"> </font><font face="Arial"><br>
<br>
</font><font size="3"><br>
</font></div><div class="im"><font color="#5f5f5f" face="Arial" size="1"><br>
From: </font><font face="Arial" size="1">"Chris
Bartels" <</font><a href="mailto:chris@christopherbartels.com" target="_blank"><font color="blue" face="Arial" size="1"><u>chris@christopherbartels.com</u></font></a><font face="Arial" size="1">></font><font size="3">
</font><font color="#5f5f5f" face="Arial" size="1"><br>
To: </font><font face="Arial" size="1"><</font><a href="mailto:openstack@lists.launchpad.net" target="_blank"><font color="blue" face="Arial" size="1"><u>openstack@lists.launchpad.net</u></font></a><font face="Arial" size="1">>,
</font><font color="#5f5f5f" face="Arial" size="1"><br>
Date: </font><font face="Arial" size="1">31/05/2013
02:12 PM</font><font size="3"> </font><font color="#5f5f5f" face="Arial" size="1"><br>
Subject: </font><font face="Arial" size="1">[Openstack]
VM disk affinity during live migration</font><font size="3"> </font><font color="#5f5f5f" face="Arial" size="1"><br>
Sent by: </font><font face="Arial" size="1">"Openstack"
<</font><a href="mailto:openstack-bounces+glikson=il.ibm.com@lists.launchpad.net" target="_blank"><font color="blue" face="Arial" size="1"><u>openstack-bounces+glikson=il.ibm.com@lists.launchpad.net</u></font></a><font face="Arial" size="1">></font><font size="3">
</font>
<div align="center">
<hr noshade></div>
<p><font size="3"><br>
<br>
</font><font face="Calibri"><br>
Hi,</font><font size="3"> </font><font face="Calibri"><br>
</font><font size="3"> </font><font face="Calibri"><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.</font><font size="3"> </font><font face="Calibri"><br>
</font><font size="3"> </font><font face="Calibri"><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?</font><font size="3"> </font><font face="Calibri"><br>
</font><font size="3"> </font><font face="Calibri"><br>
Thanks,</font><font size="3"> </font><font face="Calibri"><br>
Chris</font><tt><font>_______________________________________________</font></tt><font face="Courier New"><br>
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