measuring IO asynchronously

[Wiktor Niesiobedzki]

2011/10/12 Patrick Proniewski <patpro at patpro.net>
>
> On 10 oct. 2011, at 20:05, Mikolaj Golub wrote:
>
> > On Mon, 10 Oct 2011 16:33:11 +0200 Patrick Proniewski wrote:
> > PP> I would like to monitor the storage on various FreeBSD servers,
> > PP> especially I/O per seconds. Is there any way to gather statistics
> > PP> about I/O via asynchronous request, lets say, for example, using a
> > PP> munin plugin?  `iostat -w 1` and `zpool iostat tank 1` are
> > PP> interesting, but not useable asynchronously.
> >
> > I use for this a simple program that I wrote some time ago. It uses devstat(9)
> > kernel interface and outputs counters, like below
> >
> > kopusha:~% devstat ada0
> > ada0:
> >        1339552256 bytes read
> > ../..
> > You can find it in ports (sysutils/devstat).
>
> Thank you Mikolaj, I'm going to give it a try!
>

What's wrong about iostat? (and how it is used by munin plugin)
%iostat -I -x
                        extended device statistics
device     r/i                  w/i             kr/i
kw/i         wait svc_t  %b
ada0     26756321.0 77603114.0 411881657.5 1192108987.0    0   3.2   1
ada1     13483063.0   1131450.0 943635180.5    43584216.0    0   5.7   0
ada2     13831313.0   1131763.0 943961104.5    43587768.0    0   5.5   0


Cheers,

Wiktor Niesiobedzki