noatime,nodiratime?

[Christoph Hellwig]

On Wed, May 19, 2010 at 09:13:38AM -0500, Stan Hoeppner wrote:
> Need a little education here.  I have a general understanding of what the
> inode access timestamps "are" but I have no idea what, if any, applications
> make use of these access times.  I see posts all over Google land saying to
> use "noatime,nodiratime,logbufs=8" for XFS mount options to increase
> performance.

Which doesn't make much sense.  First 8 log buffers has been the default
for XFS for a long time.  Second nodiratime has always been useless as
it is a strict subset of of noatime.  Now noatime isn't the default yet,
but instead relatime is, which still updates the atime in memory, but
only writes it back when the inode has other changes, or on umount.
It should give you equivalent performance to noatime, but better
functionality.