I don't have any incomplete graphs in my setup of ganglia accessed via LAN connections.
It seems a problem of Transfer-Encoding: chunked which is used by php passthru().
I modified that first run the rrdtool command to write ouput to a temporary file and then
set a Content-Length: response header.
With this modification, I don't have any incomplete graphs on my private site at the AWS Tokyo region.
I got incomplete graphs over internet connections without this modification. Here is an example screenshot for http://ganglia.wmflabs.org/latest/?c=mwreview&h=unicorn&m=load_one&r=hour&s=by%20name&hc=4&mc=2 (Note: this is not my site). I got the same problem for my private site in the AWS Tokyo region.
I don't have any incomplete graphs in my setup of ganglia accessed via LAN connections.
It seems a problem of Transfer-Encoding: chunked which is used by php passthru(). I modified that first run the rrdtool command to write ouput to a temporary file and then set a Content-Length: response header.
With this modification, I don't have any incomplete graphs on my private site at the AWS Tokyo region.