openstack team mailing list archive

[Lau Jay <jay.lau.513@xxxxxxxxx>]

Cool, Alex! I think that this is the best way for Chris.

Thanks,

Jay



2013/6/1 Alex Glikson <GLIKSON@xxxxxxxxxx>

> 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 *
> http://docs.openstack.org/trunk/openstack-compute/admin/content/host-aggregates.html
> *<http://docs.openstack.org/trunk/openstack-compute/admin/content/host-aggregates.html>).
> 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).
>
> Regards,
> Alex
>
>
>
>
> From:        Lau Jay <jay.lau.513@xxxxxxxxx>
> To:        chris@xxxxxxxxxxxxxxxxxxxxxx,
> Cc:        Alex Glikson/Haifa/IBM@IBMIL, openstack@xxxxxxxxxxxxxxxxxxx
> Date:        01/06/2013 07:39 AM
> Subject:        Re: [Openstack] VM disk affinity during live migration
> ------------------------------
>
>
>
> Hi Chris,
>
> 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.
>
> 1) Make sure SSD or SAS can be reported by nova compute, you might want to
> update nova compute driver to report those metrics?
> 2) Add a new scheduler filter to do your logic checking for SSD and SAS.
>
> Thanks,
>
> Jay
>
>
>
> 2013/6/1 Chris Bartels <*chris@xxxxxxxxxxxxxxxxxxxxxx*<chris@xxxxxxxxxxxxxxxxxxxxxx>
> >
> Thanks for your reply.
>
>
>
> 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?
>
>
>
> The SAS space is 228GB & the SSD space is only 64GB.
>
>
>
> 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.
>
>
>
> But you say it’s a work in progress so that could mean anything could
> happen.
>
>
>
> 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?
>
>
>
> Thanks.
>
>
>
> *From:* Alex Glikson [mailto:*GLIKSON@xxxxxxxxxx* <GLIKSON@xxxxxxxxxx>] *
> Sent:* Friday, May 31, 2013 7:34 AM*
> To:* *chris@xxxxxxxxxxxxxxxxxxxxxx* <chris@xxxxxxxxxxxxxxxxxxxxxx>*
> Cc:* *openstack@xxxxxxxxxxxxxxxxxxx* <openstack@xxxxxxxxxxxxxxxxxxx>*
> Subject:* Re: [Openstack] VM disk affinity during live migration
>
>
>
> 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.
>
> Regards,
> Alex
>
>
>
> From:        "Chris Bartels" <*chris@xxxxxxxxxxxxxxxxxxxxxx*<chris@xxxxxxxxxxxxxxxxxxxxxx>
> >
> To:        <*openstack@xxxxxxxxxxxxxxxxxxx*<openstack@xxxxxxxxxxxxxxxxxxx>>,
>
> Date:        31/05/2013 02:12 PM
> Subject:        [Openstack] VM disk affinity during live migration
> Sent by:        "Openstack" <*
> openstack-bounces+glikson=il.ibm.com@xxxxxxxxxxxxxxxxxxx*<openstack-bounces+glikson=il.ibm.com@xxxxxxxxxxxxxxxxxxx>
> >
> ------------------------------
>
>
>
>
> Hi,
>
> 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.
>
> 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?
>
> Thanks,
> Chris_______________________________________________
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