[collectd] huge values with tail plugin

[Manuel CISSÉ]

Hi,

On 03/09/2010 06:23 PM, Florian Forster wrote:
> Hi,
> 
> On Mon, Mar 01, 2010 at 05:30:20PM +0100, Manuel CISSE wrote:
>> […] from time to time I have huge values (last was 229.1M for "Local
>> delivered") in the RRD database.
>>
>> Does anybody what could be causing this behaviour?
> 
> this is most likely caused by a "counter reset", i.e. the counter is
> reset to zero and collectd thinks an overflow occurred.

In my config DSType is set to CounterInc (for 3 counters including those
causing problems). From what I understand, this type should just count
lines matching the specified regexp, so no reset should occur.

> This problem can be solved in one of two ways:
> 
> 1) Set a maximum value for the RRD file. You can use "rrdtool tune" to
>    do this, see the rrdtune(1) manual page. Values larger than this
>    maximum value will be discarded by RRDtool.
> 
> 2) Use the (kind of) new "derive" data type instead and set its
>    minimum [sic] value to zero. Because DERIVE doesn't handle overflows,
>    it will consider the reset to be a (huge) negative value and due to
>    the minimum value the data point will be discarded as invalid.

I'll use the first solution, thanks for the hint.

-- 
regards,
Manuel CISSE