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

From: Grzegorz Nosek <grzegorz.nosek_at_gmail.com>
Date: Thu 22 Dec 2005 - 06:23:54 GMT
Message-ID: <121a28810512212223w66afad9cy@mail.gmail.com>

2005/12/22, Herbert Poetzl <herbert@13thfloor.at>:
> >
> > 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)
> >
> > vserver-stat:
> >
> > CTX PROC VSZ RSS userTIME sysTIME UPTIME NAME
> > 135 73 1.5G 3.5G 6h25m24 1h36m13 6d15h55 v135
>
> ahem, no, actually the situation is quite different,
> and very likely the vserver-stat is just wrong (as usual)
> but before we continue here, could you add the values
> from /proc/virtual/135/limits ?

(sorry for any confusion I may have caused :) )

PROC: 21 199 450 0
VM: 103540 4411996 4294967295 0
VML: 0 4 512000 0
RSS: 65389 2818258 4294967295 0
ANON: 60509 1789099 4294967295 0
FILES: 1167 3854 8128 0
OFD: 2682 97375 4294967295 0
LOCKS: 4 60 4294967295 0
SOCK: 27 304 4294967295 0
MSGQ: 0 0 4294967295 0
SHM: 128 384 4294967295 0
SEMA: 2 2 4294967295 0
SEMS: 2 2 4294967295 0

(up-to-date vserver-stat - it's 6am and the load is lower)

135 31 1.4G 967.3M 8h01m30 1h54m59 7d03h44 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.
>
> ahem, no, actually the situation is quite different,
> and very likely the vserver-stat is just wrong (as usual)
> but before we continue here, could you add the values
> from /proc/virtual/135/limits ?
>
> > > > - 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 :)
>
> hmm, but that does not have much todo with disk I/O
> those are the virtual memory stats :)

vmstat as in vmstat -d :) or bi/bo (and maybe si/so) columns of plain vmstat

> (btw, something interesting too, but hard to account
> per context, as it happens on the host)
>

With a big enough dose of optimism, it just might be doable :)

r/b columns (TASK_RUNNING, TASK_UNINTERRUPTIBLE accounting) should be easy

swpd/free/buff/cache (memory accounting) is already (mostly?) done

si/so (swap in/out) and bi/bo (block in/out) could be done via the new
per-context cfq or hacking something else together

in (per-context interrupts) are pointless probably :)

cs (context switch accounting) could also be done, I think (e.g.
counting switches _into_ or _out_of_ a process of xid=n)

us/sy/id/wa (cpu usage% in different states) is done already (at least
user/system)

> > Yeah, I think I can just graph total_forks from /proc/virtual/*/cvirt
> > :) I was trying to put as many ideas as possible.
>
> and this is definitely appreciated!
> keep 'em coming ...
>

as soon as I "invent" something :)

> > Well, I can't. The limits are enforced by pam_limits.so which isn't
> > used at all.
>
> ahem, well, then use them, no?
> correct me if I'm wrong, but that is what pam was designed
> to do, and it should do it's job quite fine if given a
> chance to do so ...
>

Not if spawning a hundred processes per second (guessing, didn't get
round to graphing the fork rate yet). Also, the set limits are
relevant in the process and child processes only, so e.g. nproc
limiting is kind of pointless.

> > 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).
>
> why not just make sure to invoke the required pam modules
> when you activate a user based service ...
>

See above, IMHO it just won't fly.

Best regards,
 Grzegorz Nosek
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Received on Thu Dec 22 06:24:16 2005

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