On Thu, 16 Apr 2009, Ugo Bellavance wrote:
Ugo Bellavance a écrit :
I'm running a CentOS 4. server and I sometimes face a weird problem.
It is a weird performance problem, and here is how I discovered it.
This server runs OpenVZ virtual machines, and one of them is an asterisk
server for my personal use. The first symptom of the problem is that
the voice quality became flaky. So I logged on the server to see what
could be eating cpu cycles, when I ran top, it took almost one minute
before top actually showed. Another hint is that when I run dstat (a
monitoring utility that is a mix of iostat and vmstat and other stats),
I often get a "missed xx ticks", where xx is a number.
Another hint is that pings are really slow. Even pinging localhost is
very long. The first reply is fast, but the second takes ages to come.
I am glad that my dstat tool provided you the information about missing
ticks, because all the other tools were basicly giving you wrong
statistics.
Dstat's statistics are wrong too, but at least it is providing you with a
hint you shouldn't trust the numbers. :)
How to fix this for OpenVZ I can't tell, but I am sure the OpenVZ forums
have smart people with an insight.
If you find that information I am very interested to know what the
solution is for OpenVZ. (Since you're running their kernel, I would have
thought this would not have been an issue though)
Thanks for keeping us posted !
--
-- dag wieers, dag@xxxxxxxxxx, http://dag.wieers.com/ --
[Any errors in spelling, tact or fact are transmission errors]
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