From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from dkim1.fusionio.com ([66.114.96.53]:55485 "EHLO dkim1.fusionio.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965843Ab3HHR37 (ORCPT ); Thu, 8 Aug 2013 13:29:59 -0400 Received: from mx1.fusionio.com (unknown [10.101.1.160]) by dkim1.fusionio.com (Postfix) with ESMTP id 716DC7C064D for ; Thu, 8 Aug 2013 11:29:59 -0600 (MDT) Date: Thu, 8 Aug 2013 13:29:57 -0400 From: Josef Bacik To: John Williams CC: Subject: Re: Why does btrfs benchmark so badly in this case? Message-ID: <20130808172957.GG16712@localhost.localdomain> References: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" In-Reply-To: Sender: linux-btrfs-owner@vger.kernel.org List-ID: On Thu, Aug 08, 2013 at 09:13:04AM -0700, John Williams wrote: > Phoronix periodically runs benchmarks on filesystems, and one thing I > have noticed is that btrfs always does terribly on their fio "Intel > IOMeter fileserver access pattern" benchmark: > > http://www.phoronix.com/scan.php?page=article&item=linux_310_10fs&num=2 > > Here, btrfs is more than 6 times slower than ext4, and about 3 times > slower than XFS. > > Lest we attribute it to an unavoidable downside of COW filesystems and > move on...no, we cannot do that, because ZFS does well here -- btrfs > is about 6 times slower than ZFS! > > Note that btrfs does quite well in the other Phoronix benchmarks. It > is just the fio fileserver benchmark that btrfs has problems with. > > What is going on here? Why is btrfs doing so poorly? Excellent question, I'll get back to you on that. Thanks, Josef