<font size=2 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"><font size=3 color=blue><u>http://docs.openstack.org/trunk/openstack-compute/admin/content/host-aggregates.html</u></font></a><font size=2 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 size=2 face="sans-serif">Regards,</font>
<br><font size=2 face="sans-serif">Alex</font>
<br><font size=2 face="sans-serif"><br>
</font>
<br>
<br>
<br><font size=1 color=#5f5f5f face="sans-serif">From:
</font><font size=1 face="sans-serif">Lau Jay <jay.lau.513@gmail.com></font>
<br><font size=1 color=#5f5f5f face="sans-serif">To:
</font><font size=1 face="sans-serif">chris@christopherbartels.com,
</font>
<br><font size=1 color=#5f5f5f face="sans-serif">Cc:
</font><font size=1 face="sans-serif">Alex Glikson/Haifa/IBM@IBMIL,
openstack@lists.launchpad.net</font>
<br><font size=1 color=#5f5f5f face="sans-serif">Date:
</font><font size=1 face="sans-serif">01/06/2013 07:39 AM</font>
<br><font size=1 color=#5f5f5f face="sans-serif">Subject:
</font><font size=1 face="sans-serif">Re: [Openstack]
VM disk affinity during live migration</font>
<br>
<hr noshade>
<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 size=3 color=blue><u>chris@christopherbartels.com</u></font></a><font size=3>></font>
<br><font size=2 color=#004080 face="Calibri">Thanks for your reply.</font>
<p><font size=2 color=#004080 face="Calibri"> </font>
<p><font size=2 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>
<p><font size=2 color=#004080 face="Calibri"> </font>
<p><font size=2 color=#004080 face="Calibri">The SAS space is 228GB &
the SSD space is only 64GB.</font>
<p><font size=2 color=#004080 face="Calibri"> </font>
<p><font size=2 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>
<p><font size=2 color=#004080 face="Calibri"> </font>
<p><font size=2 color=#004080 face="Calibri">But you say it’s a work in
progress so that could mean anything could happen.</font>
<p><font size=2 color=#004080 face="Calibri"> </font>
<p><font size=2 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>
<p><font size=2 color=#004080 face="Calibri"> </font>
<p><font size=2 color=#004080 face="Calibri">Thanks.</font>
<p><font size=2 color=#004080 face="Calibri"> </font>
<p><font size=2 face="Tahoma"><b>From:</b> Alex Glikson [mailto:</font><a href=mailto:GLIKSON@il.ibm.com target=_blank><font size=2 color=blue face="Tahoma"><u>GLIKSON@il.ibm.com</u></font></a><font size=2 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 size=2 color=blue face="Tahoma"><u>chris@christopherbartels.com</u></font></a><font size=2 face="Tahoma"><b><br>
Cc:</b> </font><a href=mailto:openstack@lists.launchpad.net target=_blank><font size=2 color=blue face="Tahoma"><u>openstack@lists.launchpad.net</u></font></a><font size=2 face="Tahoma"><b><br>
Subject:</b> Re: [Openstack] VM disk affinity during live migration</font>
<p><font size=3> </font>
<p><font size=2 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 size=2 face="Arial"><br>
Regards,</font><font size=3> </font><font size=2 face="Arial"><br>
Alex</font><font size=3> </font><font size=2 face="Arial"><br>
<br>
</font><font size=3><br>
</font><font size=1 color=#5f5f5f face="Arial"><br>
From: </font><font size=1 face="Arial">"Chris
Bartels" <</font><a href=mailto:chris@christopherbartels.com target=_blank><font size=1 color=blue face="Arial"><u>chris@christopherbartels.com</u></font></a><font size=1 face="Arial">></font><font size=3>
</font><font size=1 color=#5f5f5f face="Arial"><br>
To: </font><font size=1 face="Arial"><</font><a href=mailto:openstack@lists.launchpad.net target=_blank><font size=1 color=blue face="Arial"><u>openstack@lists.launchpad.net</u></font></a><font size=1 face="Arial">>,
</font><font size=1 color=#5f5f5f face="Arial"><br>
Date: </font><font size=1 face="Arial">31/05/2013
02:12 PM</font><font size=3> </font><font size=1 color=#5f5f5f face="Arial"><br>
Subject: </font><font size=1 face="Arial">[Openstack]
VM disk affinity during live migration</font><font size=3> </font><font size=1 color=#5f5f5f face="Arial"><br>
Sent by: </font><font size=1 face="Arial">"Openstack"
<</font><a href="mailto:openstack-bounces+glikson=il.ibm.com@lists.launchpad.net" target=_blank><font size=1 color=blue face="Arial"><u>openstack-bounces+glikson=il.ibm.com@lists.launchpad.net</u></font></a><font size=1 face="Arial">></font><font size=3>
</font>
<div align=center>
<hr noshade></div>
<p><font size=3><br>
<br>
</font><font size=2 face="Calibri"><br>
Hi,</font><font size=3> </font><font size=2 face="Calibri"><br>
</font><font size=3> </font><font size=2 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 size=2 face="Calibri"><br>
</font><font size=3> </font><font size=2 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 size=2 face="Calibri"><br>
</font><font size=3> </font><font size=2 face="Calibri"><br>
Thanks,</font><font size=3> </font><font size=2 face="Calibri"><br>
Chris</font><tt><font size=2>_______________________________________________</font></tt><font size=2 face="Courier New"><br>
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