From: Eric Sandeen <sandeen@redhat.com>
To: Justin Piszcz <jpiszcz@lucidpixels.com>
Cc: linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org,
Alan Piszcz <ap@solarrain.com>
Subject: Re: EXT4 is ~2X as slow as XFS (593MB/s vs 304MB/s) for writes?
Date: Fri, 26 Feb 2010 18:51:45 -0600 [thread overview]
Message-ID: <4B886CA1.9050906@redhat.com> (raw)
In-Reply-To: <alpine.DEB.2.00.1002261922010.8247@p34.internal.lan>
Justin Piszcz wrote:
> 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?
Aside from Dmitry's suggestion to time sync as well (although for 10G, you are
likely not leaving much in cache) I'd ask:
What kernel version? what xfsprogs/e2fsprogs version?
Were the filesystems created to align with raid geometry?
mkfs.xfs has done that forever; mkfs.ext4 only will do so (automatically)
with recent kernel+e2fsprogs.
-Eric
> 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.
> --
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next prev parent reply other threads:[~2010-02-27 0:51 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-02-27 0:31 EXT4 is ~2X as slow as XFS (593MB/s vs 304MB/s) for writes? Justin Piszcz
2010-02-27 0:46 ` Dmitry Monakhov
2010-02-27 1:05 ` Justin Piszcz
2010-02-27 0:51 ` Eric Sandeen [this message]
2010-02-27 1:08 ` Justin Piszcz
2010-02-27 1:12 ` Eric Sandeen
2010-02-27 1:28 ` Eric Sandeen
2010-02-27 10:14 ` Justin Piszcz
2010-02-27 10:51 ` Justin Piszcz
2010-02-27 11:09 ` Justin Piszcz
2010-02-27 11:36 ` Justin Piszcz
2010-02-28 5:42 ` tytso
2010-02-28 14:55 ` Justin Piszcz
2010-03-01 8:39 ` Andreas Dilger
2010-03-01 9:21 ` Justin Piszcz
2010-03-01 14:48 ` Michael Tokarev
2010-03-01 15:07 ` Justin Piszcz
2010-03-01 16:15 ` Eric Sandeen
2010-02-28 23:50 ` Dave Chinner
2010-03-02 0:08 ` Eric Sandeen
2010-03-02 0:37 ` Eric Sandeen
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