On 22/11/18 at 10:10, Didier Kryn wrote:
> Le 21/11/2018 à 17:11, Alessandro Selli a écrit :
>>> 1) A separate /usr serves no practical purpose on a Debian/Devuan
>>> system
>>    Yes it does, and they were already listed:
>>
>>
>> 1) mounting /usr with different mount options (like barrier, ro,
>> nodev etc);
>
>
> chown -R a-w /bin
> chown -R a-w /sbin
> chown -R a-w /lib


  Please read up man mount(8) and get yourself an idea of what mount
options are and do, as you evidently don't have a clue.


>>
>> 2) having /usr mounted over the network keeping / local;
>>
>> 3) having a /usr partition shared by several local installs that are
>> booted on different / filesystems;
>>
>> 4) having the smallest possible / filesystem to ease recovery of a
>> botched system.
>>
>>
>     This is all fine with a custom OS, not when it is maintained by a
> package manager.


  Yes, of course.  And guess what?  My systems are *all* customized,
because no group of package managers gets my needs and desires perfect,
and this is one of the reasons I run GNU/Linux on my PCs and laptops
instead of Windows or MacOSX.  Which is natural, as package managers
have to setup a distribution that must satisfy a large number of use
cases, some of which are in constrast to each other (such as
power-compilation server vs. workstation for network security scanning
and assessment).


> Inconsistencies between the different filesystems on which the package
> manager operates will just make it mad.


  Kernel maintainers have a much tougher life than just having to decide
where their binaries are going to sit.  Yet they manage.


> Your OS may still be usable but not updatable.


  Wrong.  Split / and /usr Unix systems have been around for decades and
they have been upgradable.  Your "solution" instead:

chown -R a-w /bin
chown -R a-w /sbin
chown -R a-w /lib


would make them not.


> I have realized this after two decades of crazy partitionning.


  Your sysadmin failures prove nothing concerning good, longstanding
filesystem layout practices, their reasons to exist and the possibility
of sysadmins to be able to customize their GNU/Linux installation the
way they choose.


> /home should definitely be separated and well protected (RAID where
> possible, backups), /usr/local (or /local) may as well, /opt
> also,since Debian does not use it. But the part of the OS (which is
> managed by dpkg) better stays on one single partition.


  There's no reason to do so other than a few corner cases (like
clusters).  Again, contrary to the Free(lol!)desktop people I am not
keen at imposing my views and choices onto others, those who refere a
merged / -> /usr filesystem should be able to do so.  But they
definitely keep their hands off *my* systems and stop trying to funnel
*their* preferences down my throat against my will.



--
Alessandro Selli <alessandroselli@???>
VOIP SIP: dhatarattha@???
Chiave firma e cifratura PGP/GPG signing and encoding key:
BA651E4050DDFC31E17384BABCE7BD1A1B0DF2AE