Aggregate: Bytes to bits

[korlaplankton]

Hello. Danger: Cacti n00b.

I would like to use to aggregate plugin (0.70 B2 -- yes, we need to upgrade!) to create some graphs from some switch interfaces. The switch's graph template uses 'bits/sec'.

When creating the aggregate graph, each item has a "Turn Bytes in to bits" CDEF by default. Is this going to skew the results? Would the correct CDEF be 'none'?

I notice that on another Cacti install with a slightly more recent version of aggregate (.75) it seems to default to _MAKE 0.

Thank you for any insights!

[gandalf]

You should first study the PDF provided with the plugin. All CDEFs starting with an underscore are special purpose CDEFs and should not interfere. In general, all items will carry there "old" CDEFs. They will turn to "_Make 0" only in case you choose to _only_ print totals (then you order us to _suppress_ all original data sources)
R.

[korlaplankton]

Thank you, I will definitely re-read the PDF now that I have a slightly better understanding how things work.

I wonder if you could confirm or deny this specific case, though. Are the graphs (bits/sec) created using the aggregate's Bytes to Bits CDEF wrong? Basically, would the total be 8 times as much as it should be, because the data is already bits/sec but the aggregate items are applying a Bytes to Bits CDEF?

I will read and understand the PDF. Promise

Thank you,

[gandalf]

To consider the approach, I need output from Graph Management in DEBUG mode
- for the "basic graph"
- for the aggregate
It's all in there, no magic outside. Even an aggregated graph is a stupid, normal Cacti graph. Once it is in place, there's nothing magic with it. It only saves time to do things manually
R.

[korlaplankton]

The output is attached. Thanks so much for having a look!

Based on my limited understanding it appears that the both the aggregate and the basic graph are doing 'bytes in to bits' so I guess that means the aggregate is showing values 8 times higher than reality?

Thanks again,

[gandalf]

Based on my limited understanding it appears that the both the aggregate and the basic graph are doing 'bytes in to bits' so I guess that means the aggregate is showing values 8 times higher than reality?

No; there's no problem in those statements.
CDEF's are used to convert values stored in RRD files to display them in the graph.
So, both examples show, that data stored in rrd files are multiplied by 8 (to convert Bytes to Bits). And this is correct.
R.

[korlaplankton]

OK, I understand how that works now. Thanks so much for taking the time to help me!