Re: [Vserver] Wiki : HowTo graph vserver usage with cacti

From: Grzegorz Nosek <>
Date: Wed 21 Dec 2005 - 17:51:51 GMT
Message-ID: <>

2005/12/21, Herbert Poetzl <>:
> > - network traffic (again, somewhat faster than iptables stats, a'la
> > /proc/net/dev maybe)
> this will have to wait until ngnet handles it, as with
> the current implementation the iptables accounting is
> the fastest you get (if you are concerned about on
> wire packages) ...
> an alternative is the socket accounting, which gives
> an userspace view of transmitted data ...

I'll probably go with iptables accounting for now.

> > - reliable memory usage (current implementation apparently doesn't
> > account for shared memory, like libraries)
> hmm, please elaborate in what way this affects your
> results (i.e. why would you want to know about the
> shared memory specifically)

I'm not interested in shared memory per se, I'd just like realistic
memory usage stats. E.g. (relevant lines from various status commands)


135 73 1.5G 3.5G 6h25m24 1h36m13 6d15h55 v135

/proc/meminfo (on host)

MemTotal: 1031036 kB
MemFree: 19272 kB
SwapTotal: 508920 kB
SwapFree: 504152 kB

So I apparently have a vserver (one of several) using 3.5G of memory
on a machine with 1G installed and 0.5G of swap (hardly touched at
all), whereas in reality it's just a number of apache2 processes
sharing most of their memory.

> > - disk i/o
> as in bytes read/written from/to disk(s) by context
> or disk operations or bandwidth?

Ideally, I'd like to see virtualised /proc/vmstat :)

> > - process-related stuff, like fork rate might be useful (ideally
> > per-user but that'd be quite an overhead probably)
> hmm, fork rate can be deduced by looking at the current
> processes and the number of forks in a timely manner
> (i.e. that should be something the graphing tools do)

Yeah, I think I can just graph total_forks from /proc/virtual/*/cvirt
:) I was trying to put as many ideas as possible.

> > Also (although not a monitoring issue and actually not vserver-related
> > really but maybe somebody has a patch handy), I'd love to see per-user
> > rlimits (the PAM-enforced ones are really per-login, so e.g. apache
> > doesn't obey them at all).
> hmm, shouldn't you be able to change the pam to make
> them per user? guess this should be an userspace issue

Well, I can't. The limits are enforced by which isn't
used at all. I don't really care about limiting interactive logins
(hardly any user ever logs on these machines, most don't have shell
accounts). OTOH, I care about per-uid limiting of resources (our web
servers have a per-vhost assigned uid and I'd like to reduce the
possibility of one broken script taking out all other vhosts).

Best regards,
 Grzegorz Nosek
Vserver mailing list
Received on Wed Dec 21 17:52:10 2005

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