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From: David Nellans <david@nellans.org>
To: grant <626542@gmail.com>, fio@vger.kernel.org
Subject: Re: Strange aggregate BW
Date: Mon, 20 Jan 2014 15:29:50 -0600	[thread overview]
Message-ID: <52DD954E.7020706@nellans.org> (raw)
In-Reply-To: <748581DD-9A26-41D7-A537-58F6D6741B33@gmail.com>

On 01/20/2014 03:23 PM, grant wrote:
> Hello,
>
> I�ve got a HWRAID with 10 NL-SAS HDDs.
> All of them used in logical volume RAID6.
> I�ve tried to benchmark created volume with FIO v2.1.4:
>
> # cat seqwrite.fio
> [write]
> blocksize=512k
> filename=/dev/sda
> rw=write
> direct=1
> buffered=0
> ioengine=libaio
> iodepth=1
> runtime=10m
> numjobs=16
>
> #./fio seqwrite.fio
>
> FIO returns:
> ...
> Run status group 0 (all jobs):
>    WRITE: io=127958MB, aggrb=2132.5MB/s, minb=56530KB/s, maxb=229141KB/s..


Between some hardware raid buffering, large block transfers, and 100% 
sequential write you'll certainly be near optimal for sequential write 
I/O seen at each disk.  200MB/s/disk is higher than most folks would 
probably ballpark, but its not off by an order of magnitude or anything. 
I assume ~150MB/s sequential performance for most "good" consumer 
7200RPM drives.  Higher RPM alone could push you to ~200MB/s.
Try turning it into random I/O and if it goes to shit, then the results
are probably as-expected ;)

  parent reply	other threads:[~2014-01-20 21:29 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-01-20 21:23 Strange aggregate BW grant
2014-01-20 21:28 ` Jeff Johnson
2014-01-22 20:52   ` grant
2014-01-20 21:29 ` David Nellans [this message]
2014-01-20 21:47 ` John Williams
2014-01-22 21:11   ` grant

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