Ocfs2 users - Apr 2013 - Ocfs2 slowdowns, high amount of reads during writes

I previously wrote about slowdowns during writing and deleting files at 
the same time on an OCFS2 volume.  I've tried writeback, and it still 
slows down a lot.

I have also been doing some testings on a 2TB ocfs2 volume on a SSD.  I 
was wondering how much better it would perform on an SSD. Unfortunately, 
I have run into an issue on the SSD, where ocfs2 ends up doing a whole 
ton of reads from the volume, and never gets much of a chance to write. 
  This happens when I access the volume from 2 systems at the same time. 
  My test scripts just use dd to write various sized files to various 
directories.  Why would ocfs2 start doing a whole bunch of reads?

Thanks,

Andy

One thing that comes to mind is partition alignment.  Have you made sure 
that the partition starts at a filesystem block size boundary? Check 
with fdisk -lu

Thanks,
Herbert.

On 4/12/13 8:43 AM, Andy wrote:
> I previously wrote about slowdowns during writing and deleting files at
> the same time on an OCFS2 volume.  I've tried writeback, and it still
> slows down a lot.
>
> I have also been doing some testings on a 2TB ocfs2 volume on a SSD.  I
> was wondering how much better it would perform on an SSD. Unfortunately,
> I have run into an issue on the SSD, where ocfs2 ends up doing a whole
> ton of reads from the volume, and never gets much of a chance to write.
>    This happens when I access the volume from 2 systems at the same time.
>    My test scripts just use dd to write various sized files to various
> directories.  Why would ocfs2 start doing a whole bunch of reads?
>
> Thanks,
>
> Andy
>
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