Re: Extreme slowness with xfs [WAS: Re: Slowness with new pc]

From: Christoph Hellwig
Date: Tue Nov 25 2008 - 05:44:32 EST


On Tue, Nov 25, 2008 at 04:56:24AM -0500, Justin Piszcz wrote:
> barriers enabled:
>
> $ time bash -c 'tar xf linux-2.6.27.7.tar; sync'
> block 573932: ** Block of NULs **
> Total bytes read: 293857280 (281MiB, 1.9MiB/s)
>
> real 2m40.643s
> user 0m0.194s
> sys 0m1.541s
>
> barriers disabled:
>
> time bash -c 'tar xf linux-2.6.27.7.tar; sync'
> block 573932: ** Block of NULs **
> Total bytes read: 293857280 (281MiB, 11MiB/s)
>
> real 0m27.612s
> user 0m0.182s
> sys 0m1.617s

That's worse than usual, and even the no-barriers numbers are still
really bad. What kind of disk and controller is this? Did you
try to disable the cache with hdparm and see what that gives?

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