Changing the default for ZFS atime to off?

[Damien Fleuriot]

On 8 Jun 2013, at 20:54, "Steven Hartland" <smh at freebsd.org> wrote:

> One of the first changes we make here when installing machines
> here to changing atime=off on all ZFS pool roots.
> 
> I know there are a few apps which can rely on atime updates
> such as qmail and possibly postfix, but those seem like special
> cases for which admins should enable atime instead of the other
> way round.
> 
> This is going to of particular interest for flash based storage
> which should avoid unnessacary writes to reduce wear, but it will
> also help improve performance in general.
> 
> So what do people think is it worth considering changing the
> default from atime=on to atime=off moving forward?
> 
> If so what about UFS, same change?
> 


I strongly oppose the change for reasons already raised by many people regarding the mbox file.

Besides, if atime should default to off on 2 filesystems and on on all others, that would definitely create confusion.

Last, I believe it should be the admin's decision to turn atime off, just like it is his decision to turn compression on.

Don't mistake me, we turn atime=off on every box, every filesystem, even on Mac's HFS.
Yet I believe defaulting it to off is a mistake.