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Re: [Linux-cluster] GFS on 2.6.8.1



On Fri, Oct 01, 2004 at 04:12:23PM -0700, Daniel McNeil wrote:

> I am just starting to test and did a quick untar test to
> see approximate performance of gfs compared to ext3.
> I only have gfs mounted on 1 node for this test. 
> Here are the results:
> 
> The command run was 'time tar xf /Views/linux-2.6.8.1.tar'
> where /Views is an NFS mounted file system and the current
> working directory is in a clean file system on a single
> disk drive.
> 
> 			real		user		sys
> ext3 data=ordered	0m16.962s	0m0.552s	0m6.529s	
> ext3 data=journal	0m39.599s	0m0.501s	0m5.856s		
> gfs 1-node mounted	1m23.849s	0m0.890s	0m17.991s

For me, gfs is about 3 times slower than ext3-ordered here (FWIW I'm not
reading from NFS).  GFS with dlm and nolock were about the same.


> The 2nd test was removing the files (time rm -rf linux-2.6.8.1/)
> 
> 			real		user		sys
> ext3 data=ordered	0m1.225s	0m0.021s	0m1.048s
> ext3 data=journal	0m1.286s	0m0.024s	0m1.038s
> gfs 1-node mounted	0m49.565s	0m0.094s	0m8.191s

GFS is 5 to 6 times slower than ext3 for me on this one.

I'll let someone else give a more expert answer to your questions.  I
think you'll find, though, that in the absence of contention, locking
isn't a very significant part of the fs performance.  You can see this in
your test by trying both lock_dlm and lock_nolock modules.

> 1. Is GFS doing the equivalent of data=journal?

no, not by default

-- 
Dave Teigland  <teigland redhat com>


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