From: Jens Axboe <axboe@kernel.dk>
To: "Georg Schönberger" <gschoenberger@thomas-krenn.com>
Cc: fio@vger.kernel.org
Subject: Re: io_u error using offsets
Date: Wed, 21 Nov 2012 10:44:49 +0100 [thread overview]
Message-ID: <50ACA291.4000000@kernel.dk> (raw)
In-Reply-To: <46391624.39675.1353347182440.JavaMail.root@thomas-krenn.com>
On 2012-11-19 18:46, Georg Schönberger wrote:
> Hello,
>
> I am trying to divide a 4TB hard disk into 128 equal parts. Therefore I divide the disk size (in Bytes) with 128 - this is my increment size. Then I start several fio job rounds with the offset increasing every round by the increment. Unfortunately I get an error for the first offset not equal to 0.
> I suppose this is an issue with the offsets not being correctly aligned.
> Here is my call to fio:
> $ sudo /usr/local/bin/fio --rw=randrw --name=wd --offset=31256148672 --direct=1 --bs=64k --filename=/dev/sdi --rwmixread=100 --numjobs=1 --ioengine=libaio --runtime=60 --iodepth=16 --size=31256148672 --group_reporting --debug=all
You get the error because 31256148672 isn't a multiple of 512b (which
I'm assuming is your sector size), hence the IO will be unaligned.
Direct IO cannot be unaligned, that's why you get an EINVAL from the OS.
--
Jens Axboe
prev parent reply other threads:[~2012-11-21 9:45 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1364943454.39595.1353345861273.JavaMail.root@thomas-krenn.com>
2012-11-19 17:46 ` io_u error using offsets Georg Schönberger
2012-11-21 9:44 ` Jens Axboe [this message]
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