From: Justin Piszcz Subject: EXT4 is ~2X as slow as XFS (593MB/s vs 304MB/s) for writes? Date: Fri, 26 Feb 2010 19:31:02 -0500 (EST) Message-ID: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; format=flowed; charset=US-ASCII Cc: Alan Piszcz To: linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org Return-path: Received: from lucidpixels.com ([75.144.35.66]:48063 "EHLO lucidpixels.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966662Ab0B0AbH (ORCPT ); Fri, 26 Feb 2010 19:31:07 -0500 Sender: linux-ext4-owner@vger.kernel.org List-ID: Hello, Is it possible to 'optimize' ext4 so it is as fast as XFS for writes? I see about half the performance as XFS for sequential writes. I have checked the doc and tried several options, a few of which are shown below (I have also tried the commit/journal_async/etc options but none of them get the write speeds anywhere near XFS)? Sure 'dd' is not a real benchmark, etc, etc, but with 10Gbps between 2 hosts I get 550MiB/s+ on reads from EXT4 but only 100-200MiB/s write. When it was XFS I used to get 400-600MiB/s for writes for the same RAID volume. How do I 'speed' up ext4? Is it possible? raid0_11 disks: (XFS) # /dev/md0 /r1 xfs noatime 0 1 p63:/r1# dd if=/dev/zero of=bigfile1 bs=1M count=10240 10240+0 records in 10240+0 records out 10737418240 bytes (11 GB) copied, 18.1021 s, 593 MB/s p63:/r1# raid0_11 disks: (EXT4) # /dev/md0 /r1 ext4 noatime 0 1 # dd if=/dev/zero of=file bs=1M count=10240 10240+0 records in 10240+0 records out 10737418240 bytes (11 GB) copied, 35.3741 s, 304 MB/s p63:/r1# Other tests (ext4) p63:~# mount /dev/md0 /r1 -o data=writeback p63:~# cd /r1 p63:/r1# dd if=/dev/zero of=file bs=1M count=10240 10240+0 records in 10240+0 records out 10737418240 bytes (11 GB) copied, 39.8746 s, 269 MB/s p63:/r1# p63:~# mount /dev/md0 /r1 -o data=writeback,nobarrier p63:/r1# dd if=/dev/zero of=file bs=1M count=10240 10240+0 records in 10240+0 records out 10737418240 bytes (11 GB) copied, 40.0656 s, 268 MB/s Justin.