Re: noatime on ufs2

Hi Jamie,

> I've often wished there was the ability to set a process to "noatime" - where
> all accesses to the filesytem by the process and its children don't alter
> atime. It would be handy for those cases you describe above, such as backups
> and locate, but these days, where it matters, and is suitable, I instead
> create a filesystem snapshot, and run the process on that instead. (which is
> how "live" backups should be done anyway!)

I've mentioned your answer in another response to Lyndon Nerenberg when developing a more general argument that 'atime' is generally flawed for these kinds of use cases (finding the last use, finding files to backup, etc.).  It's true that the ability to deactivate 'atime''s implicit updates per-process would cater to more use cases, and it's an interesting idea.  Essentially, though, you can't guarantee that some applications, or simply administrators typing commands at the shell, are not going to throw away your precious access times, so can't rely (in a strong sense) on them.

Sure for backups and snapshots.  I agree you'd better have backup perimeters coinciding with file systems partitions and use snapshots to get the smoothest possible experience.  But snapshots alone do not guarantee the "correctness" of a backup (the ability to restart smoothly from it).

Cheers.

-- 
Olivier Certner