[rrd-users] Re: bogus spikes with Infiniband traffic

[Leif Neland]

Andy Riebs wrote:
> Our Voltaire Infiniband switches (and perhaps others?) don't wrap
> their traffic counters back to zero when they hit their maximum value.
> Instead, they simply report "overflow" until a procedure is run to
> reset them to zero.
>
> On one of our mid-sized clusters, a handful of port counters are
> already overflowing after a couple of hours, and more enter that
> state as the day goes on.
>
> To keep useful statistics generally available, we have a procedure
> that resets the counters to zero once a day. Unfortunately, when we
> reset the counters, rrdtool assumes that the counters have wrapped,
> and infers very large traffic bursts through little-used ports.
>
Couldn't the max parameter of rrdcreate or rrdtune be used for this?


               min and max define the expected range values for data 
supplied
               by a data source. If min and/or max any value outside the
               defined range will be regarded as *UNKNOWN*. If you do not 
know
               or care about min and max, set them to U for unknown. Note 
that
               min and max always refer to the processed values of the DS. 
For
               a traffic-COUNTER type DS this would be the maximum and 
minimum
               data-rate expected from the device.

               If information on minimal/maximal expected values is 
available,
               always set the min and/or max properties. This will help RRD-
               tool in doing a simple sanity check on the data supplied when
               running update.

      --maximum|-a ds-name:max
               alter the maximum value acceptable as input from the data
               source.  Setting max to 'U' will disable this limit.

Leif

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