Re: noatime on ufs2

On Fri, Jan 12, 2024 at 6:15 PM Dag-Erling Smørgrav wrote:
> Tomek CEDRO writes:
> > I am reading this interesting discussion and please verify my general
> > understanding:
> > 1. There is a request for change in core OS / FS mechanism of file
> > access time (atime) because of problem with mailing application?
>
> The atime mechanism is considered harmful by many because every file
> access results in a write which (even if coalesced) not only impacts
> performance but also increases wear on SSDs.  Many people turn it off.
> Even the FreeBSD installer turns it off when installing to ZFS, except
> on `/var/mail` which is a separate filesystem precisely so that it can
> have atime enabled independently of the rest of the system.  There is a
> proposal to turn it off by default.(..)

Okay, the discussion got some (and enough) traction, and its about
changing defaults only, not the underlying kernel or filesystem code
to change the atime behavior, so this can be done as an option that
user will see and can change easily in the installer.. and still good
old atime can be used where necessary whoever needs it :-)

> > 2. Linux change of approach to atime that keeps its value only around
> > last 24h so we should also change it in FreeBSD?
> >
> > 3. "realtime" is the alternative solution to keep atime intact?
>
> The Linux approach is an alternative mechanism dubbed “relatime”
> (relative access time) which instead of updating the access time on
> every access, does so only if the previous atime is either older than
> the current mtime or more than 24 h ago.

rel-atime roger! :-) :-)

Thanks DES :-)
Tomek

--
CeDeROM, SQ7MHZ, http://www.tomek.cedro.info