Sysinstall automatic filesystem size generation.

[Darren Pilgrim]

From: C. Michailidis
> 
[sysinstall FS sizing defaults]
> 
> <...> Isn't it safe to make some of the default sizes a 
> wee bit larger?  That is, a 256mb /tmp and /var doesn't seem 
> "appropriate" if you have one of these massive modern disk 
> drives.  For christ's sake, I'd gladly give up a GB or two of 
> /usr so I could build openoffice without needing to consider 
> that I may need an extra few megabytes in /var at the time of 
> the system install.
> 
<...>
> 
> Wouldn't it be smart to remove the hardcoded default sizes 
> altogether and dynamically generate them according to a 
> reasonable function?

Probably, but a template for something like this isn't simple unless
it's created as part of a general profile-based installer that would
inform sysinstall of the machine's purpose in life.  For example, a
"workstation or Windows replacement" would need several extra GB in /usr
whereas a server would get away with a much smaller /usr, but need those
extra file-systems for logs, spools and other data.

There are, however, some basic constants:

If /usr, /var and /home are on another file-system, / doesn't need to be
more than 150-200 MB.  There just isn't that much in the root
file-system.

Assuming the default log retention and no spooling, /var will likely
never grow past 50MB.  Adding a mail, web, db or log server or
increasing log retention will go well past that mark, but then such
servers should have subordinate file-systems to handle the extra data.

What comes with the OS will take less than 300MB in /usr.  /usr/src and
/usr/obj eat around 500 MB each.  /usr/local eats around 1 GB for most
servers and 3 GB on a desktop.  /usr/X11R6 is empty if X isn't
installed, the base Xorg server package is a few hundred MB and a
desktop can need several GB.  /usr/ports should have 1-2 GB just for
distfiles on a desktop built from ports and 3 GB for work if you're
building something huge, like KDE.  I size /usr/ports to 6 GB on my
desktop machines.