/ auto-sizing (Was: 9.0-BETA1 installer glithcies (i386))

[Vadim Goncharov]

Hi Nathan Whitehorn! 

On Sun, 21 Aug 2011 11:53:22 -0500; Nathan Whitehorn wrote about 'Re: 9.0-BETA1 installer glithcies (i386)':

>> (3) "Auto" creates one big / partition + SWAP. It looks very not-BSD
>> way (disk is only 8Gb, it is virtual machine).
> This is designed to ease resizing on VMs as well as to kill the 
> default-/-is-too-small problem forever. There was a great deal of 
> discussion about this several months ago; no one made a final proposal 
> for changing it.

Actually, it's simple: make / be able to survive 5 years from now (a
reasonable age before major upgrade). So, the size needs to be predicted.
http://en.wikipedia.org/wiki/File:Hard_drive_capacity_over_time.svg says
that hard disks sizes grow according to Moore's Law, 10 times per 5 years.
The FreeBSD kernel sizes grow slower, though.

As of src/usr.sbin/sysinstall/label.c CVS log:

rev 1.161: / 1 Gb   in Jul 2010
rev 1.149: / 512 Mb in Aug 2005, formulas for other pertitions provided,
           / 256 Mb if RAMsize/harddisk size gives another value
rev 1.106: / 120 Mb in Apr 2001
...added by tens of Mbs before, not doubled

So it doubles or fourths every 5 years, thus, to reserve, let's set / to
2 or 4 Gb in 2011. Also don't create /tmp partition but rather do:

lrwxr-xr-x  1 root  wheel  -        12  9 Jan  2010 /tmp -> /var/tmp/tmp
drwxrwxrwt  9 root  wheel  sunlnk 1024 23 Aug 16:55 /var/tmp/tmp

Actually, this is just most simple short-term solution for auto-sizing.
For long-term, it should be considered to merge / and /usr with separate
partitions for ports, local, and so on, that's easy on ZFS. I have on 7.x:

Filesystem     Size    Used   Avail Capacity  Mounted on
/dev/ad0s1a    1.4G    1.1G    253M    81%    /
devfs          1.0K    1.0K      0B   100%    /dev
/dev/ad0s1f    4.4G    3.9G     66M    98%    /home
/dev/ad0s1e    6.8G    4.4G    1.9G    70%    /usr/local
/dev/ad0s1d    1.9G    1.4G    412M    77%    /var
devfs          1.0K    1.0K      0B   100%    /var/named/dev

lrwxr-xr-x   1 root  wheel     13 29 дек  2009 /usr/obj -> local/BSD/obj
lrwxr-xr-x   1 root  wheel     15 29 дек  2009 /usr/ports -> local/BSD/ports
lrwxr-xr-x   1 root  wheel     13 29 дек  2009 /usr/src -> local/BSD/src

but that will cause another long boring bikesched without clear final
proposal :-) So for 9.0R it is simpler to take short-term approach.

-- 
WBR, Vadim Goncharov. ICQ#166852181       mailto:vadim_nuclight at mail.ru
[Anti-Greenpeace][Sober FreeBSD zealot][http://nuclight.livejournal.com]