/usr/home vs /home

[Da Rock]

On 02/18/12 20:22, Polytropon wrote:
> On Sat, 18 Feb 2012 00:05:49 -0600 (CST), Lars Eighner wrote:
>> It seems to me that partition and mount point are being confused to a
>> degree.  There is no reason what is mounted at /usr/home cannot be a
>> separate partition as well as if it were mounted at root.
> I thought of this fact as such an obvious thing that I
> didn't bother even mentioning it. :-)
>
> Of course, /usr/home can be a separate partition (even on
> a separate disk), just like /usr/ports or /usr/obj or even
> /usr/local could be. I've also seen systems having several
> subtrees in /export, each one being on an individual partition,
> some of them even on an own disk.
>
>
>
>> There are some
>> good reasons for the user directories (and perhaps some other data) to be on
>> a separate partition - mostly the reasons relate to ease of back up and
>> migration whether planned or emergency.  Arguments about where to mount that
>> partition are not so practical, being more in the philosophic and historical
>> realm. Pick one, recognize not everyone will be on the same page and put
>> appropriate links in.
> I'd still be interested in why this particular location has
> been chosen. The typical access path for home directories
> is /home (that's why the symlink), and as long as this
> "top level entry" points to the proper data (no matter where
> they are located), it should be fine.
>
>
>
>> There may have been a historic reason, but now it is philosophical - trying
>> to keep the system and userland distinction clear.  But there are many flaws
>> in the attempted separation. /var for example is the default location for
>> many logs, both system and user, the spools (remember news?), and databases.
>> You really cannot drop /usr into a different system and have an operational
>> result.
> Correct. Also see the difference in usage interpretation for
> /tmp (not guaranteed to be present after reboot) and /var/tmp
> (should be present in the same state after reboot).
>
> The separation of concepts FreeBSD is famous for basically is
> "the OS" (primarily /, /etc, /(s)bin, /usr/(s)bin) that provides
> the minimal functionality to bring up the operating system even
> in worst case, where only the root partition needs to be mounted,
> which can be done in read-only mode, to finally reach the single-
> user mode, and "3rd party applications" (everything in /usr/local).
> However, both system and 3rd party programs access things in /var
> or /tmp. Not having actual _user_ data in between can be a benefit
> especially when something goes wrong.
>
>
>
>> (I put the home directories, the www directory, databases and spools all on
>> the same physical partition which I mount arbitrarily at /usr/local/data. It
>> isn't exactly plug-n-play, but in tests and emergencies is has proved
>> practical to drop the partition into several linices with a high level of
>> functionally  - depending on application versioning being close to in sync.)
> And I assume you still have /home pointing to the correct location
> on that "new" path?
I think it all depends particularly on what you're using the system for, 
really. Say you were going to run a print server, or a logging server, 
or some other service, then you would arrange the system accordingly. I 
notice that the general use case of www is already arranged to provide 
this - the webroot is setup on the usr/local/www, but that could be a 
mounted partition there too; it does protect the novice.

OTOH if you were setting up a print server, you would probably put a 
spool partition specifically for that purpose where needed. That way if 
you get a lot of large print jobs you're covered.

This general layout (the traditional one, to clarify: /, /var, /tmp, 
/usr) offers the most protection and instruction to the novice user, and 
usually works well in most general cases.

I have yet to try ZFS (lack of resources really), but when I can I will 
setup a SAN and it will be interesting to see how this works and I 
probably will use a single partition. But for the general filesystem I 
doubt a single partition will cut it (I could be a stick in the mud 
though :) ), and I highly recommend this path for the new user; 
especially using a desktop.

BTW I was intending to put across the concept of /usr being user related 
- anything a user may need or use; as opposed to / for the system 
related stuff that keeps it running. Maybe I wasn't as clear as I had 
thought... :)