On Wed, Nov 30, 2016 at 2:11 PM, Sven Kieske <[email protected]> wrote:
> On 30/11/16 09:13, Yaniv Kaul wrote: > > Thanks, but it really makes no sense to me. The direct IO by the VMs is > > going to a different storage than what the host is writing to, in most > > cases. > > The host would write to the local disk, the VMs - to a shared storage, > > across NFS or block layer or so. Moreover, their IO is not buffered. > > There is very little IO coming from the host itself, generally (I hope > > so!). > > > > Partially unrelated - the trend today is actually to put NOOP on the VMs > - > > the deadline is quite meaningless, as the host scheduler will reschedule > > anyway as it see fits. > > Most likely it is also a deadline scheduler (but could be NOOP as well if > > it's an all flash array, for example). Therefore there is no reason for > > anything but simple NOOP on the VMs themselves. > > > > In short, I think it's an outdated decision that perhaps should be > > revisited. Not urgent, though. > > Y. > > I know it's not the most cared about usecase > but I'd like to add that this might affect local storage > domains, which I happen to use a lot, and maybe others too. > In which case we should change the default for local storage. BTW, when using Gluster, they have returned these values to the original values... Y. > -- > Mit freundlichen Grüßen / Regards > > Sven Kieske > > Systemadministrator > Mittwald CM Service GmbH & Co. KG > Königsberger Straße 6 > 32339 Espelkamp > T: +495772 293100 > F: +495772 293333 > https://www.mittwald.de > Geschäftsführer: Robert Meyer > St.Nr.: 331/5721/1033, USt-IdNr.: DE814773217, HRA 6640, AG Bad Oeynhausen > Komplementärin: Robert Meyer Verwaltungs GmbH, HRB 13260, AG Bad Oeynhausen > > > _______________________________________________ > Devel mailing list > [email protected] > http://lists.ovirt.org/mailman/listinfo/devel >
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