<html><head><style type="text/css"><!-- DIV {margin:0px;} --></style></head><body><div style="font-family:times new roman, new york, times, serif;font-size:12pt"><P>coreutils-4.5.3-26 is installed on RH3</P>
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<P>RH3:</P>
<P>more /etc/issue</P>
<P>Red Hat Enterprise Linux AS release 3 (Taroon Update 2) </P>
<P>uname -a</P>
<P>Linux dbcluster7 2.4.21-40.EL #1 SMP Thu Feb 2 22:12:47 EST 2006 ia64 ia64 ia64 GNU/Linux</P>
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<P> </P>
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<P>Message: 7<BR>Date: Wed, 17 Jan 2007 02:06:37 -0800 (PST)<BR>From: Luis Freitas <lfreitas34@yahoo.com><BR>Subject: Re: [Ocfs2-users] ocfs Vs ocfs2<BR>To: ocfs2-users@oss.oracle.com, ocfs-users@oss.oracle.com<BR>Message-ID: <706536.16119.qm@web51412.mail.yahoo.com><BR>Content-Type: text/plain; charset="iso-8859-1"<BR><BR>Joel,<BR> <BR> It is not using o_direct only if the coreutils package was not installed on the RH3.0 machine. (coreutils-4.5.3-41.i386.rpm ).<BR> <BR> <A href="http://oss.oracle.com/projects/coreutils/files/" target=_blank><FONT color=#0000ff>http://oss.oracle.com/projects/coreutils/files/</FONT></A><BR> <BR> If it is installed, then both tests are using O_DIRECT, and can be compared.<BR> <BR> I do not have both a OCFS and a OCFS2 environment to compare here, but I am perceiving too a very slow performance with
copy operations on the OCFS2 volume, compared to what I was used to in OCFS.<BR> <BR>Regards,<BR> Luis<BR> <BR>Joel Becker <Joel.Becker@oracle.com> wrote:<BR> On Tue, Jan 16, 2007 at 01:28:41AM -0800, GOKHAN wrote:<BR>> Hi everbody this is my first post,<BR>> I have two test server .(Both of them is idle)<BR>> db1 : RHEL4 OCFS2<BR>> db2 : RHEL3 OCFS<BR>> <BR>> I test the IO both of them<BR>> The result is below.<BR>> <BR>> db1(Time Spend)db2(Time Spend)OS Test Command<BR>> dd (1GB) (Yazma)0m0.796s0m18.420stime dd if=/dev/zero of=./sill.t bs=1M count=1000<BR>> dd (1GB) (Okuma)0m0.241s8m16.406stime dd of=/dev/zero if=./sill.t bs=1M count=1000<BR>> cp (1GB)0m0.986s7m32.452stime cp sill.t sill2.t<BR><BR>You are using dd(1), which does not use O_DIRECT. The original<BR>ocfs (on 2.4 kernels) does not really support buffered I/O well. What<BR>you are seeing is ocfs2 taking much better care of
your buffered I/Os.<BR>They will be consistent across the cluster. In the ocfs case, you are<BR>caching a lot more because these safety precautions aren't taken.<BR>HOWEVER, the most important factor is that you are not using<BR>O_DIRECT. When you actually run the database, you _will_ be using<BR>O_DIRECT (make sure to mount ocfs2 with '-o datavolume'). Without the<BR>OS caching in the way, both filesystems should run at the same speed.<BR>The upshot is that buffered I/O operations (such as plain dd(1))<BR>are often not good indicators of database speed.<BR><BR>Joel<BR><BR>-- <BR><BR>"To announce that there must be no criticism of them president, or<BR>that we are to stand by the president, right or wrong, is not only<BR>unpatriotic and servile, but is morally treasonable to the American<BR>public."<BR>- Theodore Roosevelt<BR><BR>Joel Becker<BR>Principal Software Developer<BR>Oracle<BR>E-mail: joel.becker@oracle.com<BR>Phone: (650) 506-8127<BR></P></div><br>
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