From: bugzilla-daemon@bugzilla.kernel.org
To: linux-ext4@vger.kernel.org
Subject: [Bug 71641] New: Unreasonable performance degradation in ext4 with full data journaling
Date: Fri, 07 Mar 2014 11:39:40 +0000 [thread overview]
Message-ID: <bug-71641-13602@https.bugzilla.kernel.org/> (raw)
https://bugzilla.kernel.org/show_bug.cgi?id=71641
Bug ID: 71641
Summary: Unreasonable performance degradation in ext4 with full
data journaling
Product: File System
Version: 2.5
Kernel Version: 3.4.6
Hardware: x86-64
OS: Linux
Tree: Mainline
Status: NEW
Severity: normal
Priority: P1
Component: ext4
Assignee: fs_ext4@kernel-bugs.osdl.org
Reporter: fredchang.tc@gmail.com
Regression: No
JFS provides three modes, journal, ordered and writeback.
The first mode is denoted as ‘journal mode’in the following context.
In the journal mode, data should be written twice, one for the journal area and
the other for the client file system. If the journal area and the client file
system are both located in the disk, it has at least 50% performance
degradation compared to ordered mode.
But what if we put the journal area in a ramdisk?
I did the following tests. It shows the ext4 with full data journaling has
unreasonable performance degradation even the journal area is located in the
ramdisk.
Test environment--
CPU: Intel(R) Xeon(R) CPU E3-1225 v3 @ 3.20GHz
RAM:8GB
Filesystem:Ext4
Linux version:3.4.6
RAID are composed of 6 x 1TB HD
Command: time dd if=/dev/zero of= Write_File bs=1M count=51200
Volume_type ordered_mode Journal_mode degradation
Single_disk 173MB/s 144MB/s 17%
RAID0 937MB/s 375MB/s 60%
RAID5 732MB/s 132MB/s 82%
Does anyone know where the bottleneck may be?
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next reply other threads:[~2014-03-07 11:39 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-07 11:39 bugzilla-daemon [this message]
2014-03-07 16:20 ` [Bug 71641] New: Unreasonable performance degradation in ext4 with full data journaling Theodore Ts'o
2014-03-07 16:20 ` [Bug 71641] " bugzilla-daemon
2014-03-07 17:57 ` bugzilla-daemon
2014-03-19 9:35 ` bugzilla-daemon
2014-03-20 4:09 ` bugzilla-daemon
2014-03-20 12:47 ` bugzilla-daemon
2014-03-21 8:16 ` bugzilla-daemon
2014-03-21 8:17 ` bugzilla-daemon
2014-03-21 8:44 ` bugzilla-daemon
2014-03-21 8:48 ` bugzilla-daemon
2014-03-21 16:04 ` bugzilla-daemon
2014-03-26 10:30 ` bugzilla-daemon
2014-03-26 13:40 ` bugzilla-daemon
2014-03-28 10:23 ` bugzilla-daemon
2014-03-28 10:55 ` bugzilla-daemon
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