thomathom AT gmail DOT com wrote:
> How dangerous is it to run xfs without write barriers?

http://oss.sgi.com/projects/xfs/faq.html#nulls

As long as your computer shuts down properly, sends a flush to the 
drives, and the drives manage to clear their on-board cache before power 
is removed or the chip set is reset, it's not dangerous at all.  :o)

Here's a thread from SGI's XFS mailing list from before XFS on Linux had 
barrier support:
http://oss.sgi.com/archives/xfs/2005-06/msg00149.html

Here's an informative thread on LKML with some good information:
http://lkml.org/lkml/2006/5/19/33
A analysis of the performance hit due to barriers (and a fairly vague 
suggestion on a solution) can be found at:
http://lkml.org/lkml/2006/5/22/278

The executive summary is that you can use xfs_db to change the log 
(journal) to version 2, which allows larger buffers, which reduces "the 
impact the barriers have (fewer, larger log IOs, so fewer barriers)."

Chris

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