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Re: ext3/kjournald overhead



Hi,

On Tue, Nov 06, 2001 at 03:01:42PM -0800, Carlos Knowlton wrote:
 
> I've recently installed ext3 on an 800MB RAID5
> (software) array.  I am running RedHat Linux 7.1 with
> the Linux kernel 2.4.12-ac3 on a 1GHz Pentium system
> with 128MB RAM.  I am seeing a significant amount of
> write operation slowdown when running ext3 (and
> kjournald), as opposed to my old ext2.  The problem
> seems to be associated with the times that kjournald
> is accessing the disk.  At those moments, my CPU
> utilization peaks, and network transfer is nearly
> halted until kjournald is finished. 

Could you try a "readprofile" to see where the CPU time is being
spent?  Is it in the raid layers or in ext3?

> I read in an archive of a Linux Symposium on 20 July,
> 2000 by Dr. Stephen Tweedie that, at that time, actual
> file data was being journaled as opposed to just
> metadata.  It looked like the plan was to fix that. 
> Has this been done?

Yes, ages ago.

Cheers,
 Stephen





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