xfs didn't provide redundancy for citical data structure?

[Stan Hoeppner]

hank peng put forth on 5/15/2010 10:57 AM:
> I read this paper: http://pages.cs.wisc.edu/~vshree/xfs.pdf, which
> says xfs didn't provide redundancy for citical data structure, such as
> mirror, parity. I wonder if it is so?
> If it is, is there plan to implement that for XFS developers?

This paper was published in early 2005, the research based on Linux 2.6.9,
which was released in 2004.  The analysis was performed on code that is now
~6 years old.

Are these shortcomings valid?  Have any been addressed/fixed since 2004?
Does real world usage show they're not needed, or that the development
cost/benefit ratio is too high to bother implementing the changes?

-- 
Stan