Add SUM sysctl

[Daniel Braniss]

> 
> --Kj7319i9nmIyA2yE
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> On Sat, Apr 16, 2011 at 04:46:53PM -0600, Warren Block wrote:
> >On Sat, 16 Apr 2011, dieterbsd at engineer.com wrote:
> >
> >>Suggestion 2:  The kernel may not have an official flag for single
> >>vs multi user mode but you can fake it.  Try something like
> >>"pgrep syslogd".  If syslogd is running assume multiuser mode.  If
> >>syslogd is not running assume single user mode.
> >
> >Another option: kern.hostid is set nonzero pretty early in the rc
> >scripts.
> 
> Same as getty(8). That also will not be running in SU and in most cases
> is a clear indication that nothing else is running unless you have a
> remote only machine without a console in which you have purposely
> disabled getty(8).
> 
> --=20
> 
>  Regards,
>  J. Hellenthal
>  WWJD

when something gets too complicated, it's usualy helpful to look for other ways
out:
the /(root) + /usr + kernel-debuging + src is less than 1GB, so what I
do (when diskless is not an option), I have a 2 partitions, both bootable,
and so i ALWAYS update the non active one, then
1- I always have a working / in case the update screwed something
2- I can update without problems.

my $.02

danny