[Users] Dstat plugin for OpenVZ CPU statistics

[Dag Wieers]

On Mon, 16 Oct 2006, Kir Kolyshkin wrote:

> Dag Wieers wrote:
>
> > I've just written a small dstat plugin to monitor CPU usage per VE. You can
> > find the plugin in the dstat subversion repository linked from:
> >
> >  http://dag.wieers.com/home-made/dstat/
> >
> > Dstat is much like vmstat, but modular and versatile. So you can extend it
> > with whatever counters you want to visualize, next to other counters. This
> > helps to relate counters and find/troubleshoot bottlenecks.
> >
> > This plugin can help to find the most consuming VE, or visualize how VE's
> > are matching up to each other (and the system CPU usage).
> 
> Thank you! I actually use dstat on my Gentoo note.

Great :)

 
> Speaking of counters, /proc/user_beancounters is of interest to any OpenVZ
> user. Format is described at http://wiki.openvz.org/proc/user_beancounters.
> "held" and "failcnt" columns are most "dynamic". You can use the values either
> directly, or make some consolidated figures based of formulae in wiki.

Well, I was wondering how the beancounters could be of any use. I guess it 
may be useful to see when (and maybe where) they happen, but how would it 
be displayed the most useful ? An aggregated number of all failcnt (either 
global, or per VPS) ? That way one can see if any failcnts happen, but 
they'll have to look into the beancounters themselves to know exactly 
which ones happened.

The held-changes are mostly useless to display in a dstat-fashion. Unless 
maybe if you are a developer ? There's so much information that needs an 
in-depth knowledge.

 
> Other thing that might be of interest is /proc/fairsched{,2}. These files are
> from OpenVZ Fair CPU scheduler. The only problem is looks like the format is
> not documented (well, not counting the source code).
> 
> Also, Kirill Korotaev will give us some suggestions...

By any means, if you know what is interesting and how it could be made 
visible on a single line (aggregated or not) we can make different openvz 
plugins depending on the use-case.

Kind regards,
--   dag wieers,  dag at wieers.com,  http://dag.wieers.com/   --
[all I want is a warm bed and a kind word and unlimited power]