From: Josef Bacik <jbacik@fusionio.com>
To: Kai Krakow <hurikhan77+btrfs@gmail.com>
Cc: <linux-btrfs@vger.kernel.org>
Subject: Re: Why does btrfs benchmark so badly in this case?
Date: Mon, 12 Aug 2013 09:48:40 -0400 [thread overview]
Message-ID: <20130812134840.GA2150@localhost.localdomain> (raw)
In-Reply-To: <8u3gda-evs.ln1@hurikhan77.spdns.de>
On Fri, Aug 09, 2013 at 11:35:33PM +0200, Kai Krakow wrote:
> Josef Bacik <jbacik@fusionio.com> schrieb:
>
> >> So I guess the reason that ZFS does well with that workload is that
> >> ZFS is using smaller blocks, maybe just 512B ?
> >
> > Yeah I'm not sure what ZFS does, but if you are writing over a block and
> > the size/offset isn't aligned then you'd see similar issues with ZFS since
> > it would
> > have to read+modify+write. It is likely that ZFS just is using a smaller
> > blocksize.
>
> From what I remember, ZFS uses dynamic block sizes. However, block size can
> be forced and thus tuned for workloads that require it:
>
> http://www.joyent.com/blog/bruning-questions-zfs-record-size
>
> Maybe that's the reason...
>
> It would be interesting to see how the benchmarks performed with forced
> block size.
>
When I did bs=4k in the fio job to force it to use 4k blocksizes we performed
the same as ext4 and xfs. Thanks,
Josef
next prev parent reply other threads:[~2013-08-12 13:48 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-08 16:13 Why does btrfs benchmark so badly in this case? John Williams
2013-08-08 17:29 ` Josef Bacik
2013-08-08 18:37 ` Clemens Eisserer
2013-08-08 19:40 ` Josef Bacik
2013-08-08 20:23 ` John Williams
2013-08-08 20:38 ` Josef Bacik
2013-08-09 21:35 ` Kai Krakow
2013-08-12 13:48 ` Josef Bacik [this message]
2013-08-08 20:59 ` Chris Murphy
2013-08-08 21:25 ` Zach Brown
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