[Bug 131094] Re: Heavy Disk I/O harms desktop responsiveness

Jamie Lokier jamie at shareable.org
Wed Apr 22 10:37:12 UTC 2009

Hendrik van den Boogaard wrote:
> @Jamie:
> On my 7200.11 1 TB drives (also one of the first 1 TBs on the
> market) I also disabled NCQ because I found some thread that it
> might kill the contents of the file system. If you want I can lookup
> where I found that.

I'm guessing it's barriers not being implemented or enabled properly
in the kernel?  (See ext3 "barrier=1" off by default, controversial
threads about it..)  Even if the filesystem does barriers, Linux
software RAID does not.  If it's not that, I'm interested in why NCQ
should be disabled.  In principle, if used right, it should always be
an improvement or about the same, and it would be quite bad firmware
to fail at that.

> This machine however has a SATA disk and I never experienced any
> sluggishness on this machine, so far running Hardy and Intrepid. So the
> sluggishness may even be drive specific?

It might.  There are tools, such as blktrace, which can help diagnose
if it's the drive if you know how to read the output.  It is quite
outside what I have time for though :-)

-- Jamie

Heavy Disk I/O harms desktop responsiveness
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