<div dir="ltr"><br><div class="gmail_extra"><br><div class="gmail_quote">On Wed, Nov 30, 2016 at 2:11 PM, Sven Kieske <span dir="ltr"><<a href="mailto:s.kieske@mittwald.de" target="_blank">s.kieske@mittwald.de</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><span class="">On 30/11/16 09:13, Yaniv Kaul wrote:<br>
> Thanks, but it really makes no sense to me. The direct IO by the VMs is<br>
> going to a different storage than what the host is writing to, in most<br>
> cases.<br>
> The host would write to the local disk, the VMs - to a shared storage,<br>
> across NFS or block layer or so. Moreover, their IO is not buffered.<br>
> There is very little IO coming from the host itself, generally (I hope<br>
> so!).<br>
><br>
> Partially unrelated - the trend today is actually to put NOOP on the VMs -<br>
> the deadline is quite meaningless, as the host scheduler will reschedule<br>
> anyway as it see fits.<br>
> Most likely it is also a deadline scheduler (but could be NOOP as well if<br>
> it's an all flash array, for example). Therefore there is no reason for<br>
> anything but simple NOOP on the VMs themselves.<br>
><br>
> In short, I think it's an outdated decision that perhaps should be<br>
> revisited. Not urgent, though.<br>
> Y.<br>
<br>
</span>I know it's not the most cared about usecase<br>
but I'd like to add that this might affect local storage<br>
domains, which I happen to use a lot, and maybe others too.<br></blockquote><div><br></div><div>In which case we should change the default for local storage.</div><div>BTW, when using Gluster, they have returned these values to the original values...</div><div>Y.</div><div><br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div class="HOEnZb"><div class="h5"><br>
--<br>
Mit freundlichen Grüßen / Regards<br>
<br>
Sven Kieske<br>
<br>
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