Re: [gentoo-user] Re: Anyone switched to eudev yet?

[Alan McKinnon]

On Sun, 16 Dec 2012 12:49:53 -0600
Bruce Hill <daddy@×××××××××××××××××××××.com> wrote:

> On Sun, Dec 16, 2012 at 05:10:43PM +0200, Alan McKinnon wrote:
> >
> > That was the original reason for having / and /usr separate, and it
> > dates back to the early 70s. The other reason that stems from that
> > time period is the size of disks we had back then - they were tiny
> > and often a minimal / was all that could really fit on the primary
> > system drive.
> >
> > Gradually over time this setup became the norm and people started to
> > depend on it, and more importantly, started to believe it was
> > important to retain it. It's their right to believe that.
> >
> > Recently I decided to measure if I still needed a separate /usr (I
> > was a long time advocate of retaining it). I'm in the lucky
> > position of having ~200 Linux machines, all distinctly different,
> > at my disposal, so I trawled through memory and incident logs
> > looking for cases where a separate /usr was crucial to recovery
> > after any form of error. To my surprise, I found none at all and
> > those logs go back 5 years.
> >
> > So I got to change my mind (not something I do very often I admit)
> > and concluded that separate base and user systems (/ and /usr) was
> > no longer something I needed to do - the "system" - disks, hardware
> > and the software on the disks - was very reliable, and what I
> > really needed was ability to boot from USB rescue disks. I did
> > find, not unsurprisingly, that I also really needed /usr/local on a
> > separate partition but that's because of how we install our
> > in-house software here, plus our backup policies.
> >
> > It also goes without saying that these days we
> > need /home, /var, /var/log and /tmp to all be on their own
> > filesystem, and we need that more than ever.
> >
> > I thought I should just toss that in the ring for people who are
> > undecided where they stand on the debate of separate / vs /usr. It's
> > what I found on our production, dev and staging servers, plus a
> > whole lot of people's personal workstations (sysadmins and devs).
> > The environment is a large corporate ISP that defies
> > categorization, we almost have at least one of every imaginable
> > use-case for running on Linux except something in the Top 100
> > SuperComputer list. I reckon it's about as representative as I'm
> > ever gonna see.
> >
> > People are free to draw their own conclusions as always, and real
> > data is valuable in arriving at those conclusions. YMMV.
>
> Thanks for sharing your experience, and not just your emotions. One
> of my favorite quotes is, "A man with an experience is not subject to
> a man with an argument."

There's a few things I completely left out - /usr/portage
and /usr/distfiles - I forgot all about those.

For years now I manually move those to /var as I consider /usr to
be mostly read-only, plus the portage tree and distfiles are hungry.
They form two cases where separate mounts are highly desirable.

The other thing I didn't comment on is /usr mounted ro over NFS. The
only current valid case I've heard of is school and university labs,
and one of those is the only one I've ever seen. Not something I ever
work with to be honest. I would like to know how prevalent /usr as an
NFS mount is in the world out there.


-- 
Alan McKinnon
alan.mckinnon@×××××.com