I have opposite statistics - OCFS (v1) was very slow on 'tar x' and other 'appending file' operations, and OCFSv2 had compatible speed *(with ext3), except it used a lot of CPU to syncronize locks (system was SLES9 SP3 kernel >= 244).
Moreover, db1 statuistics below looks wrong - the realistic time to 'dd from zero to 1 GB file is 18 seconds (db2). 0.7 seconds means tht data are in the cache, which it turn means that you cant use OCFSv1 at all on such scenario. ----- Original Message ----- From: Luis Freitas To: [email protected] ; [EMAIL PROTECTED] Sent: Wednesday, January 17, 2007 2:06 AM Subject: Re: [Ocfs2-users] ocfs Vs ocfs2 Joel, 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 ). http://oss.oracle.com/projects/coreutils/files/ If it is installed, then both tests are using O_DIRECT, and can be compared. 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. Regards, Luis Joel Becker <[EMAIL PROTECTED]> wrote: On Tue, Jan 16, 2007 at 01:28:41AM -0800, GOKHAN wrote: > Hi everbody this is my first post, > I have two test server .(Both of them is idle) > db1 : RHEL4 OCFS2 > db2 : RHEL3 OCFS > > I test the IO both of them > The result is below. > > db1(Time Spend)db2(Time Spend)OS Test Command > dd (1GB) (Yazma)0m0.796s0m18.420stime dd if=/dev/zero of=./sill.t bs=1M count=1000 > dd (1GB) (Okuma)0m0.241s8m16.406stime dd of=/dev/zero if=./sill.t bs=1M count=1000 > cp (1GB)0m0.986s7m32.452stime cp sill.t sill2.t You are using dd(1), which does not use O_DIRECT. The original ocfs (on 2.4 kernels) does not really support buffered I/O well. What you are seeing is ocfs2 taking much better care of your buffered I/Os. They will be consistent across the cluster. In the ocfs case, you are caching a lot more because these safety precautions aren't taken. HOWEVER, the most important factor is that you are not using O_DIRECT. When you actually run the database, you _will_ be using O_DIRECT (make sure to mount ocfs2 with '-o datavolume'). Without the OS caching in the way, both filesystems should run at the same speed. The upshot is that buffered I/O operations (such as plain dd(1)) are often not good indicators of database speed. Joel -- "To announce that there must be no criticism of them president, or that we are to stand by the president, right or wrong, is not only unpatriotic and servile, but is morally treasonable to the American public." - Theodore Roosevelt Joel Becker Principal Software Developer Oracle E-mail: [EMAIL PROTECTED] Phone: (650) 506-8127 _______________________________________________ Ocfs2-users mailing list [email protected] http://oss.oracle.com/mailman/listinfo/ocfs2-users __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com ------------------------------------------------------------------------------ _______________________________________________ Ocfs2-users mailing list [email protected] http://oss.oracle.com/mailman/listinfo/ocfs2-users
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