From: Linux Raid Study <linuxraid.study@gmail.com>
To: Roberto Spadim <roberto@spadim.com.br>
Cc: linux-raid@vger.kernel.org
Subject: Re: iostat with raid device...
Date: Fri, 8 Apr 2011 15:10:45 -0700 [thread overview]
Message-ID: <BANLkTik0S7JfN+ccs+oKPHADkvZSH_aEzw@mail.gmail.com> (raw)
In-Reply-To: <BANLkTim6ANxfFoiMfHe1JOyTrtCQ-02gsw@mail.gmail.com>
Thanks for pointing this out...I did observe this but forgot to
mention in the email...
Can someone give some insight into this.
Thanks.
On Fri, Apr 8, 2011 at 3:05 PM, Roberto Spadim <roberto@spadim.com.br> wrote:
> another question... why md have more tps? disk elevators? sector size?
>
> 2011/4/8 Linux Raid Study <linuxraid.study@gmail.com>:
>> Hello,
>>
>> I have a raid device /dev/md0 based on 4 devices sd[abcd].
>>
>> When I write 4GB to /dev/md0, I see following output from iostat...
>>
>> Ques:
>> Shouldn't I see write/sec to be same for all four drives? Why does
>> /dev/sdd always have higher value for BlksWrtn/sec?
>> My strip size is 1MB.
>>
>> thanks for any pointers...
>>
>> avg-cpu: %user %nice %system %iowait %steal %idle
>> 0.02 0.00 0.34 0.03 0.00 99.61
>>
>> Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn
>> sda 1.08 247.77 338.73 37478883 51237136
>> sda1 1.08 247.77 338.73 37478195 51237136
>> sdb 1.08 247.73 338.78 37472990 51245712
>> sdb1 1.08 247.73 338.78 37472302 51245712
>> sdc 1.10 247.82 338.66 37486670 51226640
>> sdc1 1.10 247.82 338.66 37485982 51226640
>> sdd 1.09 118.46 467.97 17918510 70786576
>> sdd1 1.09 118.45 467.97 17917822 70786576
>> md0 65.60 443.79 1002.42 67129812 151629440
>> --
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>
>
>
> --
> Roberto Spadim
> Spadim Technology / SPAEmpresarial
>
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next prev parent reply other threads:[~2011-04-08 22:10 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-04-08 19:55 iostat with raid device Linux Raid Study
2011-04-08 22:05 ` Roberto Spadim
2011-04-08 22:10 ` Linux Raid Study [this message]
2011-04-08 23:46 ` NeilBrown
2011-04-09 0:40 ` Linux Raid Study
2011-04-09 8:50 ` Robin Hill
2011-04-11 8:32 ` Linux Raid Study
2011-04-11 9:25 ` Robin Hill
2011-04-11 9:36 ` Linux Raid Study
2011-04-11 9:53 ` Robin Hill
2011-04-11 10:18 ` NeilBrown
2011-04-12 1:57 ` Linux Raid Study
2011-04-12 2:51 ` NeilBrown
2011-04-12 19:36 ` Linux Raid Study
2011-04-13 18:21 ` Linux Raid Study
2011-04-13 21:00 ` NeilBrown
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