From: Spelic <spelic@shiftmail.org>
To: Jens Axboe <JAxboe@fusionio.com>
Cc: "fio@vger.kernel.org" <fio@vger.kernel.org>
Subject: Re: Again on IOPS higher than expected in randwrite 4k
Date: Mon, 3 Jan 2011 04:26:57 -0700 [thread overview]
Message-ID: <4D21B281.8040501@shiftmail.org> (raw)
In-Reply-To: <4D21AD7D.7090707@fusionio.com>
On 01/03/2011 12:05 PM, Jens Axboe wrote:
> On 2011-01-02 05:12, Spelic wrote:
>
>> Hello, I just subscribed, I noticed that some 20 days ago there was a
>> thread on "IOPS higher than expected on randwrite, direct=1 tests" on
>> this ML. It's curious because I subscribed to report basically the
>> same thing.
>>
>> With Hitachi 7k1000 HDS721010KLA330 (maybe the same drives as
>> Sebastian) I am seeing the same problem of IOPS too high with FIO, up
>> to 300 IOPS per disk (up to 500 per disk with storsave=performance on
>> my 3ware but that's probably cheating). I am doing 4k random writes.
>>
>> I followed the discussion, I don't really agree with the point at the
>> end of the discussion, so I'd like to bump this thread again.
>>
>> My impression is that these drives do not honor the flush or FUA.
>> (Directio uses flush or FUA right? you can be sure that data is on the
>> platters after directio right? Anyway I also set fsync=1 and nothing
>> changed)
>>
> O_DIRECT does not imply flush of FUA, I'm afraid. It arguably should use
> FUA, but currently it does not.
>
Oh I see.
But if I add fsync=1 I still get 300 IOPS per disk, or even 500 on very
short seeks, so again I'd say these disks are cheating.
Do you agree?
next prev parent reply other threads:[~2011-01-03 11:26 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-01-02 4:12 Again on IOPS higher than expected in randwrite 4k Spelic
2011-01-03 11:05 ` Jens Axboe
2011-01-03 11:26 ` Spelic [this message]
2011-01-03 14:10 ` Jens Axboe
2011-01-05 11:45 ` Spelic
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=4D21B281.8040501@shiftmail.org \
--to=spelic@shiftmail.org \
--cc=JAxboe@fusionio.com \
--cc=fio@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.