The code I referred to is the Hobbit code not the RRD stuff. Whilst RRD may well allow negative numbers it looks like Hobbit is not coded correctly to allow it, at least not the source code I am looking at. I know that there is an unofficial patch for Hobbit but have no idea whether the code I am looking at is this version or not, not if that code has this same bug.

If you compiled your own Hobbit then you can follow these instructions to modify the source:

Change to the Hobbit source directory. Edit the hobbitd/rrd/do_ncv.c file. Go to line 54, which looks like this: l = val + strspn(val, "0123456789.");

Add a - after the . so it looks like this: l = val + strspn(val, "0123456789.-");

Compile and install as per standard instructions.

|\/|artin

-----Original Message-----
From: Ralph Mitchell [mailto:ralphmitchell at gmail.com] 
Sent: 28 July 2008 16:18
To: hobbit at hswn.dk
Subject: Re: [hobbit] No graph for negative clock offset


Judging by the man page, negative values are OK.  The first

entry in the EXAMPLE section of "man rrdcreate" reads:

          rrdtool create temperature.rrd --step 300 \
             DS:temp:GAUGE:600:-273:5000 \
             RRA:AVERAGE:0.5:1:1200 \
             RRA:MIN:0.5:12:2400 \
             RRA:MAX:0.5:12:2400 \
             RRA:AVERAGE:0.5:12:2400

         This sets up an RRD called temperature.rrd which

accepts one tempera- ture value every 300 seconds. If no new data is supplied for more than 600 seconds, the temperature becomes *UNKNOWN*. The minimum acceptable value is -273 and the maximum is 5'000.

Ralph Mitchell



On Mon, Jul 28, 2008 at 9:24 AM, Ward, Martin

<Martin.Ward at colt.net> wrote:

	Funnily enough I am looking at the Hobbit code that

deals with RRD data at the moment. If you are using the NCV capabilities then it looks like you can't have negative numbers. The generic NCV (Number, Colon, Value) code looks for numbers only, no signs (somewhere near line 70 in hobbitd/rrd/do_ncv.c): val = l + strspn(l, " \t"); l = val + strspn(val, "0123456789."); I have no idea if RRD is able to accept/store negative values, but if it is, it should be a simple case of adding the + and - characters to the last line listed above to make what you want possible. |\/|artin

	-----Original Message-----
	From: David Stuffle [mailto:david at stufflemail.com]
	Sent: 28 July 2008 14:28
	To: hobbit at hswn.dk
	Subject: [hobbit] No graph for negative clock offset
	
	
	Hi all,
	None of my clock offset graphs graph anything when the

clock offset from a host is a negative number. Only positive number work. Anyone having the same thing happen or know how to fix? I'm running a snapshot 4.3.0-0.20080103 Thanks David To unsubscribe from the hobbit list, send an e-mail to hobbit-unsubscribe at hswn.dk

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Please note that incoming emails will be automatically scanned to eliminate potential viruses and unsolicited promotional emails. For more information refer to www.colt.net or contact us on +44(0)20 7390 3900.