Re: Lower HD transfer rate with NCQ enabled?

[Paa Paa]

Mark Lord wrote:
> > > This is mostly a problem with the WD Raptor drive, and some other WD 
> > > drives.
> > > I have not yet encountered/noticed the problem with other brands.
> >
> > Sounds like this is a serious bug in the WD firmware.
>
> For personal systems, yes.  For servers, probably not a bug.

In my case the choice of IO scheduler affected the result of "hdparm -t" 
significantly. With Deadline I got identical result with NCQ and wihout NCQ. 
It was only with CFQ when I got worse results with NCQ than without it.

What might be the reason CFQ+NCQ gived so much worse throughput with "hdparm 
-t"?

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