Re: [gentoo-user] tmp on tmpfs

On 17-05-23 at 22:16, Ian Zimmerman wrote:
> So what are gentoo users' opinions on this matter of faith?
I use an ext4 partition backed by zram. Gives me ~3x compression on the
things I normally have lying around there (plain text files) and ensures
that anything I throw there (or programs throw there) gets cleaned up on
reboot.

> I have long been in the camp that thinks tmpfs for /tmp has no
> advantages (and may have disadvantages) over a normal filesystem like
> ext3, because the files there are normally so small that they will stay
> in the page cache 100% of the time.
I've never actually benchmarked this. Most of the things I notice that
tend to end up there are temporary build files generated during
configure stages or temporary log files used by various programs (clang
static analyzer). Even if the entire file stays in the page cache, it'll
still generate IO overhead and extra seeks that might slow down the rest
of your system (unless your /tmp is on a different hard drive) which on
spinning rust will cause slowdowns while on an ssd it'll eat away at
your writes (which you may or may not have to worry about).

> But I see that tmpfs is the default with systemd.  Surely they have a
> good reason for this? :)
Or someone decided they liked the idea and made it the default and
nobody ever complained (or if they did were told to just change it on
their system). 

Either way, it'd be nice if someone actually benchmarked this.

-- 
Simon Thelen