Am 13.04.2014 um 06:39 schrieb Alexandre DERUMIER <aderum...@odiso.com>:
>>> And I read: >>> https://www.mail-archive.com/ceph-users@lists.ceph.com/msg06890.html >>> >>> Niw don't get me wrong, erring on the side of safety is quite sensible, >>> but the impact of having no caching by qemu is in the order of a 2 >>> magnitudes easily. > > > Thanks for link reference ! Works for me too. Had already done 100'drets of migrations. Greets, Stefan > > > > > ----- Mail original ----- > > De: "Christian Balzer" <ch...@gol.com> > À: "Alex Crow" <ac...@integrafin.co.uk> > Cc: ceph-users@lists.ceph.com > Envoyé: Samedi 12 Avril 2014 17:56:07 > Objet: Re: [ceph-users] qemu + rbd block driver with cache=writeback, is live > migration safe ? > > > Hello, > >> On Sat, 12 Apr 2014 16:26:40 +0100 Alex Crow wrote: >> >> Hi. >> >> I've read in many places that you should never use writeback on any kind >> of shared storage. Caching is better dealt with on the storage side >> anyway as you have hopefully provided resilience there. In fact if your >> SAN/NAS is good enough it's supposed to be best to use "none" as the >> caching algo. >> >> If you need caching on the hypervisor side it would probably better to >> use something like bcache/dmcache etc. > And I read: > https://www.mail-archive.com/ceph-users@lists.ceph.com/msg06890.html > > Niw don't get me wrong, erring on the side of safety is quite sensible, > but the impact of having no caching by qemu is in the order of a 2 > magnitudes easily. > > Beers, > > Christian > >> Cheers >> >> Alex >> >> >>> On 12/04/14 16:01, Alexandre DERUMIER wrote: >>> Hello, >>> >>> I known that qemu live migration with disk with cache=writeback are >>> not safe with storage like nfs,iscsi... >>> >>> Is it also true with rbd ? >>> >>> >>> If yes, it is possible to disable manually writeback online with qmp ? >>> >>> Best Regards, >>> >>> Alexandre >>> _______________________________________________ >>> ceph-users mailing list >>> ceph-users@lists.ceph.com >>> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com >> >> _______________________________________________ >> ceph-users mailing list >> ceph-users@lists.ceph.com >> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > > > -- > Christian Balzer Network/Systems Engineer > ch...@gol.com Global OnLine Japan/Fusion Communications > http://www.gol.com/ > _______________________________________________ > ceph-users mailing list > ceph-users@lists.ceph.com > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > _______________________________________________ > ceph-users mailing list > ceph-users@lists.ceph.com > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com _______________________________________________ ceph-users mailing list ceph-users@lists.ceph.com http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
