Dear Experts, The graphs that I got from collectd's Apache plugin seemed to show too few connections, so I investigated.
It seems that when using the (newish) "event" mpm, Apache can put some connections into an "async" state. Typically this is connections that are in keep-alive, waiting for another request from the same host, and (possibly) connections that are sending a file using sendfile(). In this state the connections do not take up a server thread. In the server-status?auto output, these connections do not appear as characters in the Scoreboard: line. Instead they are counted in additional lines, ConnsAsyncWriting, ConnsAsyncKeepAlive and ConnsAsyncClosing. Here is a fragment of my server-status?auto : BusyWorkers: 1 IdleWorkers: 49 ConnsTotal: 7 ConnsAsyncWriting: 2 ConnsAsyncKeepAlive: 3 ConnsAsyncClosing: 0 Scoreboard: ....................................................................................................______________W___________________________________.................................................................................................................................................................................................................................................................................................................................................................................................................................................................. collectd shows just one connection. I think that, ideally, I'd like to graph the ConnsTotal: value. Any thoughts anyone? On a related matter, the reason I was looking at this was that my Apache instance was misbehaving and I was hoping to see some clues about what was going wrong in the collectd graphs. But there were just gaps, because collectd does an exponential backoff when its attempt to read server-status fails after 10 seconds. This is exactly the wrong behaviour - when the server is being very slow to respond I want collectd to try harder to get the statistics! (I confess I have not yet looked to see if there is any way to adjust this.) Thanks, Phil. _______________________________________________ collectd mailing list collectd@verplant.org https://mailman.verplant.org/listinfo/collectd