[Xymon] Another weirdness - RRD info has gaps

Henrik Størner henrik at hswn.dk
Sat Aug 4 07:58:48 CEST 2012


On 03-08-2012 23:42, Betsy Schwartz wrote:
> n Fri, Aug 3, 2012 at 4:17 PM, Tim McCloskey <tm at freedom.com> wrote:
>> I've seen this before but I don't remember the exact cause, I just remember that working on rrd stuff tended to add gray hair.  Do both of these graphs have essentially the same rrd configs?  If the foo.rrd files do not contain the detail for the tests I would truncate foo.rrd, and recheck my [foo] graph stanza. (rather, save a copy off foo.rrd first)
>
> It's got *some* data but it's got gaps. I dropped the test, erased the
> RRD file and put it back, and I am *still* seeing gaps.
>
> I swear my two tests are getting the exact same info:

What Xymon version are you running on the Xymon server ? Anything before 
4.3.4 has a known bug that can cause this.

Are there any errors logged in your rrd-status.log / rrd-data.log files?

You're sending the messages with a lifetime of 12 hours. How often are 
you sending these messages ? If not once every 5 minutes, then the 
RRD-file must have a non-standard "step" and "heartbeat" value - you can 
check this with "rrdtool info myfile.rrd" - here's one from my server:

filename = "/var/lib/xymon/rrd/jorn.hswn.dk/la.rrd"
rrd_version = "0003"
step = 300
<snip>
ds[la].minimal_heartbeat = 600

"step" is how often you're sending updates. "minimal_heartbeat" 
determines how long time may pass between updates before the data is 
considered invalid - in this case, if more than 600 seconds pass between 
two updates, then the data is not considered valid and will be ignored 
*unless* another update arrives within the next 600 seconds.

The "heartbeat" can be changed with rrdtuune. "step" cannot - you'll 
have to export the rrd-file to XML, edit the XML file and then restore 
the rrd-file from the XML.


Regards,
Henrik





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