Why does my graph look like this

[tman]

I am polling a Windows server to check on DHCP addresses free and in use. I've built the data and graph templates, and the values are being polled correctly in the log file;

08/09/2005 03:25:14 PM - CMDPHP: Poller[0] Host[36] DS[707] SNMP: v2: server1.domain.co.uk, dsname: DhcpNoAddInUse, oid: .1.3.6.1.4.1.311.1.3.2.1.1.2, output: 473
08/09/2005 03:25:14 PM - CMDPHP: Poller[0] Host[36] DS[706] SNMP: v2: server1.domain.co.uk, dsname: DhcpNoAddFree, oid: .1.3.6.1.4.1.311.1.3.2.1.1.3, output: 35

The graph though, looks completely weird. The values are not being displayed, and I'm getting odd spikes. All other graphs being polled (50 odd devices) are showing correct. The rra files are being updated ok. I'm using Cacti on Win32;

v0.8.6f (patched)
MySQL v4.1.12a
PHP v4.3.11
Net-snmp 5.1.2
rrdtool v1.2.11

Anyone have any idea why the graph should look like this?

Thanks

[TheWitness]

You should be using a GUAGE RRD type and not the others.

TheWitness

[tman]

You should be using a GUAGE RRD type and not the others.

TheWitness

I've tried using Counter and Gauge, deleting the rra's and re-creating them each time. If you do an snmpwalk on the oid, it returns as;

SNMPv2-SMI::enterprises.311.1.3.2.1.1.2.0 = Counter32: 469

So I think it should be a Counter. Do you agree?

Thanks

[stevew]

The MIB (snmp) data type is not related to the rrdtool data source type. COUNTER is for continuously increasing numbers and stores a per-second rate.

GAUGE is what you want.

The spikes on your graph correspond to increases of 1 or 2 - and decreases, which result in overflows... therefore huge numbers... are probably ignored due to the graph max value.

For instance if you poll every 300 seconds and receive 469 when the previous result was 468, the COUNTER data type calculates a value of (469-468)/300=0.0033 or 3.3 milli-addresses per second. Which isn't much use.

[TheWitness]

Steve's got it down to a science.

TheWitness

[tman]

Well, following Steve's advice, I went back to using GAUGE as the data type, but it didn't make any difference. I then decided to reboot the whole server running Cacti, and what do you know, the graphs sprung into life.

Isn't life weird!