From: Jim Mauro Subject: Re: ZFS, XFS, and EXT4 compared Date: Thu, 30 Aug 2007 14:33:48 -0400 Message-ID: <46D70D8C.8010203@sun.com> References: <1188454611.23311.13.camel@toonses.gghcwest.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: zfs-discuss@opensolaris.org, linux-ext4@vger.kernel.org, xfs@oss.sgi.com To: "Jeffrey W. Baker" Return-path: In-reply-to: <1188454611.23311.13.camel@toonses.gghcwest.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: zfs-discuss-bounces@opensolaris.org Errors-To: zfs-discuss-bounces@opensolaris.org List-Id: linux-ext4.vger.kernel.org I'll take a look at this. ZFS provides outstanding sequential IO performance (both read and write). In my testing, I can essentially sustain "hardware speeds" with ZFS on sequential loads. That is, assuming 30-60MB/sec per disk sequential IO capability (depending on hitting inner or out cylinders), I get linear scale-up on sequential loads as I add disks to a zpool, e.g. I can sustain 250-300MB/sec on a 6 disk zpool, and it's pretty consistent for raidz and raidz2. Your numbers are in the 50-90MB/second range, or roughly 1/2 to 1/4 what was measured on the other 2 file systems for the same test. Very odd. Still looking... Thanks, /jim Jeffrey W. Baker wrote: > I have a lot of people whispering "zfs" in my virtual ear these days, > and at the same time I have an irrational attachment to xfs based > entirely on its lack of the 32000 subdirectory limit. I'm not afraid of > ext4's newness, since really a lot of that stuff has been in Lustre for > years. So a-benchmarking I went. Results at the bottom: > > http://tastic.brillig.org/~jwb/zfs-xfs-ext4.html > > Short version: ext4 is awesome. zfs has absurdly fast metadata > operations but falls apart on sequential transfer. xfs has great > sequential transfer but really bad metadata ops, like 3 minutes to tar > up the kernel. > > It would be nice if mke2fs would copy xfs's code for optimal layout on a > software raid. The mkfs defaults and the mdadm defaults interact badly. > > Postmark is somewhat bogus benchmark with some obvious quantization > problems. > > Regards, > jwb > > _______________________________________________ > zfs-discuss mailing list > zfs-discuss@opensolaris.org > http://mail.opensolaris.org/mailman/listinfo/zfs-discuss >