On Wednesday, November 11, 2015, Wido den Hollander <[email protected]> wrote:

> On 11/10/2015 09:49 PM, Vickey Singh wrote:
> > On Mon, Nov 9, 2015 at 8:16 PM, Wido den Hollander <[email protected]
> <javascript:;>> wrote:
> >
> >> On 11/09/2015 05:27 PM, Vickey Singh wrote:
> >>> Hello Ceph Geeks
> >>>
> >>> Need your comments with my understanding on straw2.
> >>>
> >>>    - Is Straw2 better than straw ?
> >>
> >> It is not persé better then straw(1).
> >>
> >> straw2 distributes data better when not all OSDs are equally
> >> sized/weighted.
> >>
> >>>    - Is it straw2 recommended  for production usage ?
> >>>
> >>
> >> I'm using it in multiple clusters and it works fine.
> >>
> >
> > Yes i followed your update on twitter  :)
> >
> >
> >>
> >>> I have a production Ceph Firefly cluster , that i am going to upgrade
> to
> >>> Ceph hammer pretty soon. Should i use straw2 for all my ceph pools ?
> >>>
> >>
> >> I would upgrade to Hammer first and make sure that ALL clients are
> updated.
> >>
> >> In case you are using KVM/Qemu, you will have to stop those processes
> >> first and start them again before they are using the new code.
> >>
> >
> > Thanks a lot for this pointer, i didn't knew this. So restarting KVM /
> QEMU
> > process effect running VMs ? ( some downtime )
> >
>
> Yes. You can also (live) migrate to another host since that will spawn
> Qemu with fresh code on the other host.
>
> But you have to make sure all running/connected clients support straw2
> before you enable straw2.


I believe straw2 only requires monitor support -- unlike the tuna led
involved in executing CRUSH, straw2 is just about how the OSD/bucket
weights get converted into a sort of "internal" straw weight. That's done
on the monitors and encoded into the maps.

Right?
-Greg




>
> >
> >>
> >>> Also how can i change from straw to straw2. ( should i decompile crush
> >> map
> >>> and replace all straw with straw2) ?
> >>>
> >>
> >> Yes, that's it. Extract, decompile, replace, compile, inject.
> >>
> >> $ ceph osd getcrushmap -o crushmap
> >> $ crushtool -d crushmap -o crushmap.txt
> >> $ <edit crushmap.txt>
> >> $ crushtool -c crushmap.txt -o crushmap.new
> >> $ ceph osd setcrushmap -i crushmap.new
> >>
> >> In case stuff goes wrong, inject the original crushmap.
> >>
> >> Wido
> >>
> >
> > Thank You so much for your time in replying to my queries :)
> >
> >
> >>
> >>> Please suggest
> >>>
> >>> Thank You in advance.
> >>>
> >>> - Vickey -
> >>>
> >>>
> >>>
> >>> _______________________________________________
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> >>> [email protected] <javascript:;>
> >>> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
> >>>
> >>
> >>
> >> --
> >> Wido den Hollander
> >> 42on B.V.
> >> Ceph trainer and consultant
> >>
> >> Phone: +31 (0)20 700 9902
> >> Skype: contact42on
> >> _______________________________________________
> >> ceph-users mailing list
> >> [email protected] <javascript:;>
> >> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
> >>
> >
>
>
> --
> Wido den Hollander
> 42on B.V.
> Ceph trainer and consultant
>
> Phone: +31 (0)20 700 9902
> Skype: contact42on
> _______________________________________________
> ceph-users mailing list
> [email protected] <javascript:;>
> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
>
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