Questions - Average and Total Bandwidth

[craigeb]

Hi,
I'm looking to utilize cacti for colocation and dedicated internet customers. For the model we're offering, we basically need to see the entire bandwidth usage for the month.

How accurate is the monthly total in and total out calculations cacti produces? I'm a little concerned by the 2 hour average statement underneath the graph, since I'm not really sure what it's referring to. For the monthly total bandwidth, is it taking information from a single snapshot every 2 hours, and just adding these figures for the monthly period?


Also, I had my graphs set at in/out with 95th percentile. I switched a few graphs and data sources to in/out with total bandwidth, and one of my graphs showed the exact same total in/total out, which definitely isn't the case. I cleared the poller cache, waiting, and looked again, and now the other 2 show identical in/out info, and first one is fine. Have any ideas on what I should do to get this data pulling in correctly?

Thanks,
Craig

[craigeb]

Also, I had my graphs set at in/out with 95th percentile. I switched a few graphs and data sources to in/out with total bandwidth, and one of my graphs showed the exact same total in/total out, which definitely isn't the case. I cleared the poller cache, waiting, and looked again, and now the other 2 show identical in/out info, and first one is fine. Have any ideas on what I should do to get this data pulling in correctly?

I've fixed this problem. I had to go into graph management and reapply the correct data sources. Both were set to traffic_out for some reason.

Can anybody enlighten me regarding the total bandwidth calculations?

Thanks,
Craig

[gandalf]

How accurate is the monthly total in and total out calculations cacti produces? I'm a little concerned by the 2 hour average statement underneath the graph, since I'm not really sure what it's referring to. For the monthly total bandwidth, is it taking information from a single snapshot every 2 hours, and just adding these figures for the monthly period?

RRDTOOL aggregates data based on 5min readings. AVERAGE aggregation for e.g. 30 mins is done by adding 6 values and dividing by 6. MAX aggregation is done by taking the max value out of 6 values ...
Same holds for 2 h aggregation respectively.
So it depends on your pricing policy. Does it depend on peaks? Then you should use MAX aggregates. Does it depend on averages/volume? Then you should use AVERAGE aggregates.
Please read the tutorials at http://www.rrdtool.org for a deeper insight
There are _lots_ of postings on this in the forum
Reinhard