From: Jacques Gelinas (jack_at_solucorp.qc.ca)
Date: Thu 23 Jan 2003 - 21:11:48 GMT
On Thu, 16 Jan 2003 16:18:01 -0500, =?iso-8859-2?Q?Marcin_Sucho=BFebrski?= wrote
> Hello,
>
> I didn't see in docs any number (max numer) of virtual server to run on one phisical
> computer. Which limitations (ex. file handlers, devices number) are the lowest and
> decide on the maximum numer of running vservers?
>
> I'll be numer of 200, 500, 1000? We can take situation that i have enough resources
> (CPU, memory, disks)..
>
> I think it will be about 240-250?
A vserver does not use any resource by itself. There is no "invisible" overhead
for each vserver. The overhead comes from the tasks you are running inside the
vserver. In general a vserver will run minimally
syslogd
crond
and sometime
sshd
So this is the overhead. Now each vserver will do something useful. Run apache
or run mysql for example. Running a task inside a vserver uses the same resources
as running it outside (a vserver).
Memory wize, because of the unification, most task will be sharing the text
(program code), so this is fairly efficient.
Now you may want to run very specialised vservers, potentially running a single
task without cron and syslog. So goes down the overhead.
For sure it also depends on the activity of the services. The real issue is probably
there. If you run 50 vservers each running apache and taking enough hit, you may
have performance problem.
Anyway, you will have to try. All I can say is that vserver do not use resource
by itself. It only depends on the apps you are running inside and they are using
the same resources inside or outside a vserver.
Hope this helps.
PS: If you run cron on redhat distro, before of task like updatedb. With 10 vservers
they will all wake up at 4 in the morning. The load will go up. You may want to
disable this.
---------------------------------------------------------
Jacques Gelinas <jack_at_solucorp.qc.ca>
vserver: run general purpose virtual servers on one box, full speed!
http://www.solucorp.qc.ca/miscprj/s_context.hc