On Thu, 2015-04-30 at 15:58 +0200, Joerg Reisenweber wrote:

> Poettering clearly understood the implications and outright rejected the
> rationale, by claiming nowadays it wasn't modern anymore to have a small root-
> fs and a separate partition for /usr

He is correct on this point. One should always obey the rules until you
understand why the rule was made and the consequences of breaking it.
Once upon a time the rule was that / should have everything needed to
complete the booting of the system and to get a rescue shell. But Linux
already violates that rule in that a naked kernel often can't access or
mount / itself, which is why an initrd is usually used to start things
off.

Once that is accepted as something unavoidable, and it is unavoidable in
a world of lvm, multiple software RAID implementations, wide variety of
filesystems and such, the idea of / having the tools for mounting
everything else is impractical. It made sense when / was on a fixed
disk with driver support baked into the kernel and there was only one or
two filesystems available.

Now as for other assertions in this thread that the FHS itself is
obsolete and violations of it should not be considered a bad thing, just
no. No. As I said above, first read and understand it so you
understand when it is ok to violate it and when it should be updated.
The FHS was carefully designed to accomodate things like NFS root,
readonly NFS mounting of parts of the system, mandating things like
*/share/ to only contain arch neutral data, etc. A lot of work is there
to encode existing and historical practice in a lot more use cases than
any one developer will likely be familiar with.