Re: selectively disabling atime updates?

[Matthias Kretschmer <kretschm%cs.uni-bonn.de@localhost>]

On Thu, May 31, 2012 at 04:23:12PM +0200, Edgar Fuß wrote:
> > A null mount should do the job and this fstab entry should work:
> > 
> >     /path/to/orig /path/to/ov[e]rlay null ro,noatime 
> Unfortunately, that doesn't work. I get
>       mount_null: -o atime: option not supported
> (yes, that's "atime", not "noatime").
> 
> Just mounting ro doesn't seem to stop the atime updates.
> 
> Other suggestions to selectively disable atime updates?

I would think that the atime updates are generated by
mount_null/nullfs when the corresponding file in the null-mount
is accessed and the nullfs has to access the original file.

How about using fss for it instead.  If I understand you correctly
you want noatime for backup purposes.  So you might just create
a snapshot of the filesystem you want to backup and access the
snapshot when performing the backup.  This should ensure, that the
changes are written to the location specified by fssconfig(8) and
are lost when you unconfigure the fss afterwards.  Has the
nice effect to make the backup from a non-changing set, too.

--
Matthias Kretschmer