No errors, blank graph

[Sammitch]

I'm working on getting some graphs running for our new spam filter stats, but I'm not getting any data points on the graph or any errors in the log that would indicate what I've done wrong. I'm not a Cacti pro by any means, I've basically tried to replicate all of the configuration of the ucd/net Load Average graphs, so I'll list out what I've done and hopefully someone can point out where I've gone wrong.

First, a simple snmpwalk from the Cacti server against the OID I'm trying to graph, 5min average scan time in ms x1000:

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# snmpwalk -v 2c -c public canit03 .1.3.6.1.4.1.10055.1.2.1.4.3
SNMPv2-SMI::enterprises.10055.1.2.1.4.3 = INTEGER: 355358

Looks good, so I created a Data Template using the "Get SNMP Data" method, changing the default values:

• Maximum Value: 60000000 [60s]
• Type: GAUGE
• OID: .1.3.6.1.4.1.10055.1.2.1.4.3

Now a quick graph template started with the default values, added a Graph Template Item:

• selected my new Data Source
• picked a color
• Item Type: AREA
• Consolidation Function: AVERAGE
• CPRINT Type: Normal
• Text Format: 5min avg

Now I went to an existing device which has other working graphs pulled from SNMP, added the new Graph Template, clicked 'Create Graphs for this Host', checked the box, hit save, waited for the graph to appear.

Blank. Gave it a few more minutes, blank. Gave it all weekend, still blank. [see attachment]

As well, an rrdtool dump of the rrd file shows every row contains NaN. Any idea what I'm doing wrong?

[Deviloper]

1. Did you specify a max. and min. value? If the wrong max. min Value is set the graph will never show anything.

2. Set your cacti poller into debugging mode and check if the returned value is what you expected.

3. check the rrd-rra-files. Are they updated.

4. Trie rebuild the graph template, sometimes the graph templates become buggy during editing.

[Sammitch]

1. Did you specify a max. and min. value? If the wrong max. min Value is set the graph will never show anything.

2. Set your cacti poller into debugging mode and check if the returned value is what you expected.

3. check the rrd-rra-files. Are they updated.

4. Trie rebuild the graph template, sometimes the graph templates become buggy during editing.

1. Yes, the min/max are 0/30,000,000 respectively. The data cannot be negative, and rarely exceeed 1,000,000.

2. Hadn't tried this yet, but seems to work just fine:

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11/23/2010 09:55:03 AM - CMDPHP: Poller[0] Host[2] DS[244] SNMP: v2: canit03.network.net, dsname: can_scan5m, oid: .1.3.6.1.4.1.10055.1.2.1.4.3, output: 321451

3. The timestamp is updated, but the rrd still contains nothing but NaN.

4. At this point I am confident that the graph template is not the current problem.

[Sammitch]

I still don't exactly know what the problem was, but I seem to have fixed the problem by doing the following:

• turning on 'Data Source Debug'
• copying the rrdtool create command
• running it on the server.

Please bear in mind if you've arrived from Google and want to try this that I am 99% sure this will empty out any existing data in the RRA.

I still have a pile of Data Sources that I will be creating and graphing in the same way, so if I happen to figure what actually caused this issue I will certainly post the issue.

[Deviloper]

Do you use Graphcaching? If so check clean up the cache.

Do you use any special non ascii characers in graph, rrd or template configuration? This was a killerbug in 0.8.7e... i searched 4 whole days until i found it.

Try to break it down to a minimum.. use a line graph with no extra features and check out if that works. I had a bug in rrd with AREA-items.

[Sammitch]

I've created another 7 data templates, 4 new graphs, and applied them to 10 hosts. I ran into this issue just one more time, and the cause is that when I originally created the data template I had not set the maximum correctly before the data source was created. It was not obvious to me at the time that changing the maximum in the data template would not change it in the existing RRAs.

As far as I am aware either deleting and recreating the data source or what I've described above should solve the problem. If you have valid data points in the RRA that you don't want wiped out you would have to dump the RRA, modify the XML with the new max, and then restore it.