rawhide report: 20101019 changes

[Chris Adams]

Once upon a time, Matthew Garrett <mjg59 at srcf.ucam.org> said:
> On Tue, Oct 19, 2010 at 02:43:33PM +0100, Paul Howarth wrote:
> > This despite the FHS says (right at the top of Chapter 3, the Root 
> > Filesystem):
> > 
> >    /usr, /opt, and /var are designed such that they may be located on other
> >    partitions or filesystems.
> > 
> > Do we *really* want to head this way, ignoring bugs resulting from 
> > having /usr on a different partition such as 
> > http://bugzilla.redhat.com/#626007, which is what led to this?
> 
> What's the benefit in having /usr or /opt as separate filesystems?

A smaller / that is written to less often is less susceptible to errors.
If you don't allocate enough space for / up front, you can move /usr and
/opt to separate filesystems later.  /opt can be completely
unpredictable in space usage, due to vendor RPMs dumping stuff in /opt
(see Dell's OMSA, that puts everything, including logs, under /opt).

When disk was expensive, /usr was often the biggest consumer of space,
so it would be shared across the network, but that's not a big issue
anymore (and RPM doesn't really support shared /usr IIRC).

I personally don't use a separate /usr on desktops, only on servers.  On
my servers, /usr is mounted read-only, as an extra protection against
accidental (or even intentional) screw-ups.  It also means that I don't
waste I/O cycles on updating atimes on often-used binaries and libraries
(which of course could also be done with noatime).

I've seen some boot-from-flash setups with /usr on a hard drive.

Basically, if Fedora is going to follow the FHS at all, bugs like 626007
should be fixed, not ignored because somebody doesn't like a separate
/usr.

-- 
Chris Adams <cmadams at hiwaay.net>
Systems and Network Administrator - HiWAAY Internet Services
I don't speak for anybody but myself - that's enough trouble.