[rrd-users] Maximum number of data sources/max cdef size.

[Simon Hobson]

George Barnett wrote:

>I'm aggregating boxes into a graph to draw a cluster and I'm getting
>null values.
>
>Is there a maximum number of datasources in 1 graph?
>
>Is there a maximum size of a cdef?
>
>I've found that if I do this with only a few DS's, it works fine.  Maybe
>somebody has tried this before?

<snip>

>"CDEF:gclient_requests=1aggavgclient_requests,2aggavgclient_requests,+,3aggavgclient_requests,+,4aggavgclient_requests,+,5aggavgclient_requests,+,6aggavgclient_requests,+,7aggavgclient_requests,+,8aggavgclient_requests,+,9aggavgclient_requests,+,10aggavgclient_requests,+,11aggavgclient_requests,+,12aggavgclient_requests,+,13aggavgclient_requests,+,14aggavgclient_requests,+,15aggavgclient_requests,+,16aggavgclient_requests,+,17aggavgclient_requests,+"\

Are you aware that if ANY of the values is unknown them the result is 
unknown ? So for example, if you were not collecting samples for one 
system for a while, then you would have a gap in the graph.

You have to do a test for unknown values and replace them with zeros 
before adding them all together. Have a look back through the 
archives, it's come up before.