[hobbit] TCP/IP stats (bits/s) limited to 100M

[Werner (gmail Lists)]

Hi,

	The 110Mbits/s value you get, does really point to 32bit counter
wrap, because with 32bit BYTE counter, measured every 5 minutes,
110Mbits/s is (aprox) the maximum you can count without wrapping the
counter.

	As Henrik explained bellow, it should not be a "wrap" done by
hobbit nor RRD. I'm think you need to look at you OS counters directly
and see if they're wrapping in less than 5 minutes.

	If you on Solaris / SunOS you could use something like the
bellow, and watch if any of the counters wraps 32 bit value (4294967295
if i recall correctly)

(host)$> while [ 1 ]; do date; netstat -s | \
egrep "(tcpInInorderBytes|tcpOutDataBytes)" ; sleep 60; done

Example output:
Wed Jun 28 09:28:28 EDT 2006
        tcpOutDataSegs      =5864959    tcpOutDataBytes     =4273878800
        tcpInInorderSegs    =2670997    tcpInInorderBytes   =725993348

	(CARE) With RRD it's possible to come around of this OS
limitation by feeding the data in shorter times, lets say every 2
minutes. RRD will take care of computing (making) the values "correct"
for the steep size used to create the RRD (in hobbit's case 300 secs). 

	I'm not exactly sure how /and or if hobbit will be happy in
receiving client info quicker than every 5 minutes, but i think it
should be transparent.

	Hope this can give you some help.

	Regards
	Werner

----------------------- Original Message -----------------------
From:    henrik at hswn.dk (Henrik Stoerner)
To:      hobbit at hswn.dk
Date:    Wed, 28 Jun 2006 13:09:13 +0200
Subject: Re: [hobbit] TCP/IP stats (bits/s) limited to 100M
----

> On Wed, Jun 28, 2006 at 11:42:14AM +0200, Beau Olivier wrote:
> > Hi,
> > 
> > this looks like tcp-data going arround the 32bit counter problem...
> > are your counters 32 bit ? could you give us a copy of them ?
> 
> The RRD files are created as "DERIVE" datatypes with a minimum value of
> 0, which should handle 32/64-bit counter overflows automatically.
> (See the rrdcreate man-page).
> 
> Note that Hobbit never does any calculations on these values, it passes
> them directly (as strings) to the RRDtool functions. 
> 
> 
> Regards,
> Henrik
> 
>