Re: Strange delete performance using XFS

Justin Piszcz
2007-04-04T14:24:50Z

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On Wed, 4 Apr 2007, Thomas Kaehn wrote:

> Hi Justin,
>
> On Wed, Apr 04, 2007 at 10:12:48AM -0400, Justin Piszcz wrote:
>> On Wed, 4 Apr 2007, Justin Piszcz wrote:
>>> On Wed, 4 Apr 2007, Thomas Kaehn wrote:
>>> $ time for i in `seq 1 100000`; do dd if=/dev/zero of=$i bs=1k count=20
>>>> /dev/null 2>&1; done
>>>
>>> 1. Six 400GB SATA drives using SW RAID5:
>>> real 6m24.411s
>>> user 0m43.097s
>>> sys 2m17.350s
>>>
>>
>> The removals:
>> The benchmark:
>> $ time rm -rf test
>>
>> 1. Six 400GB SATA drives using SW RAID5:
>> real 0m33.996s
>> user 0m0.057s
>> sys 0m8.101s
>
> thanks for your bechmark. To my mind this clearly shows that my
> setup is wrong at some point. I'll try again with your mount options.
>
> Ciao,
> Thomas
> --
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>

My guess is mkfs.xfs cannot optimzie for your array like it can with a SW
RAID device because it cannot see what is undereath it. Have you tried
making a SW RAID? I also use optimized parameters for my SW RAID1/5 as
well FYI.

Justin.