From: Nathan Scott Subject: Re: ZFS, XFS, and EXT4 compared Date: Thu, 30 Aug 2007 17:07:46 +1000 Message-ID: <1188457666.24970.94.camel@edge.yarra.acx> References: <1188454611.23311.13.camel@toonses.gghcwest.com> Reply-To: nscott@aconex.com Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Cc: zfs-discuss@opensolaris.org, xfs@oss.sgi.com, linux-ext4@vger.kernel.org To: "Jeffrey W. Baker" Return-path: In-Reply-To: <1188454611.23311.13.camel@toonses.gghcwest.com> Sender: xfs-bounce@oss.sgi.com Errors-to: xfs-bounce@oss.sgi.com List-Id: linux-ext4.vger.kernel.org On Wed, 2007-08-29 at 23:16 -0700, Jeffrey W. Baker wrote: > ... xfs has great > sequential transfer but really bad metadata ops, like 3 minutes to tar > up the kernel. Perhaps this is due to the write barrier support - would be interesting to try a run with the "-o nobarrier" mount option to XFS. With external logs, write barriers are automatically disabled, which may explain: "Oddly XFS has better sequential reads when using an external journal, which makes little sense." To improve metadata performance, you have many options with XFS (which ones are useful depends on the type of metadata workload) - you can try a v2 format log, and mount with "-o logbsize=256k", try increasing the directory block size (e.g. mkfs.xfs -nsize=16k, etc), and also the log size (mkfs.xfs -lsize=XXXXXXb). Have fun! cheers. -- Nathan