This is a big development for us. I have not heard of this option either. I
am excited to play with this feature and the implications it may have in
improving RBD reads in our multi-datacenter RBD pools.

Just to clarify the following options:
"rbd localize parent reads = true" and "crush location = foo=bar" are
configuration options for the client's ceph.conf and are not needed for OSD
hosts as their locations are already encoded in the CRUSH map.

It looks like this is a pretty old option ( http://narkive.com/ZkTahBVu:
5.455.67 )

so I am assuming it is relatively tried and true? but I have never heard of
it before... is anyone out there using this in a production RBD environment?




On Tue, Apr 4, 2017 at 7:36 PM, Jason Dillaman <[email protected]> wrote:

> AFAIK, the OSDs should discover their location in the CRUSH map
> automatically -- therefore, this "crush location" config override
> would be used for librbd client configuration ("i.e. [client]
> section") to describe their location in the CRUSH map relative to
> racks, hosts, etc.
>
> On Tue, Apr 4, 2017 at 3:12 PM, Brian Andrus <[email protected]>
> wrote:
> > Jason, I haven't heard much about this feature.
> >
> > Will the localization have effect if the crush location configuration is
> set
> > in the [osd] section, or does it need to apply globally for clients as
> well?
> >
> > On Fri, Mar 31, 2017 at 6:38 AM, Jason Dillaman <[email protected]>
> wrote:
> >>
> >> Assuming you are asking about RBD-back VMs, it is not possible to
> >> localize the all reads to the VM image. You can, however, enable
> >> localization of the parent image since that is a read-only data set.
> >> To enable that feature, set "rbd localize parent reads = true" and
> >> populate the "crush location = host=X rack=Y etc=Z" in your ceph.conf.
> >>
> >> On Fri, Mar 31, 2017 at 9:00 AM, Alejandro Comisario
> >> <[email protected]> wrote:
> >> > any experiences ?
> >> >
> >> > On Wed, Mar 29, 2017 at 2:02 PM, Alejandro Comisario
> >> > <[email protected]> wrote:
> >> >> Guys hi.
> >> >> I have a Jewel Cluster divided into two racks which is configured on
> >> >> the crush map.
> >> >> I have clients (openstack compute nodes) that are closer from one
> rack
> >> >> than to another.
> >> >>
> >> >> I would love to (if is possible) to specify in some way the clients
> to
> >> >> read first from the nodes on a specific rack then try the other one
> if
> >> >> is not possible.
> >> >>
> >> >> Is that doable ? can somebody explain me how to do it ?
> >> >> best.
> >> >>
> >> >> --
> >> >> Alejandrito
> >> >
> >> >
> >> >
> >> > --
> >> > Alejandro Comisario
> >> > CTO | NUBELIU
> >> > E-mail: [email protected]: +54 9 11 3770 1857
> >> > _
> >> > www.nubeliu.com
> >> > _______________________________________________
> >> > ceph-users mailing list
> >> > [email protected]
> >> > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
> >>
> >>
> >>
> >> --
> >> Jason
> >> _______________________________________________
> >> ceph-users mailing list
> >> [email protected]
> >> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
> >
> >
> >
> >
> > --
> > Brian Andrus | Cloud Systems Engineer | DreamHost
> > [email protected] | www.dreamhost.com
>
>
>
> --
> Jason
> _______________________________________________
> ceph-users mailing list
> [email protected]
> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
>



-- 
Respectfully,

Wes Dillingham
[email protected]
Research Computing | Infrastructure Engineer
Harvard University | 38 Oxford Street, Cambridge, Ma 02138 | Room 210
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