disk and NIC io statistics via sysctl

[Stefan Parvu]

> magic secret kernel backdoor interfaces, all these userland tools are
> using documented interfaces such as sysctl to get their info.  (There
> may be a few miscreants that open /dev/kmem and rudely poke around in
> kernel memory, but I'm not sure we have any of them in base.  The lsof
> tool in ports is one that comes to mind for that.)

Ian, understood - no magic here. I was looking to see if there are ready sysctl 
structures, arrays or hashes which can package already the mentioned stats. 
Like kern.cp_times, a very nice thing which is hidden and undocumented.

I see very big improvement in sysctl and things are much organized since FreeBSD 5.
But we will need better documentation.

Im on iostat now - to understand how throughput per disk gets calculated.

> In addition to the tools you've already mentioned that have the info you
> want, have a look at gstat for IO stats, netstat for net throughput, and
> systat for lots of stuff.

gstat, thanks. havent used that. I will look over iostat, netstat. Probable would be nice
to have a section on sysctl man page or probable something totally new which describes
cpu | mem | disk | net and kernel statistics.

Cheers,

-- 
Stefan Parvu <sparvu at systemdatarecorder.org>