[Cflowd] Flowscan graphs delaying

[Martin van den Nieuwelaar]

Scott Smith wrote:
> Background :
> I've been using Cflowd and Flowscan for over a year on the same Linux 
> box.  We've added some HD and Memory, however the OS has pretty well 
> stayed the same.
> 
> Last few weeks :
> I noticed a few weeks ago that our graphs have started falling behind. 
> Nothing has changed to the configs for over the past year.  However, 
> within the last few weeks, the graphs have started falling behind. 
> Sometimes hours behind, and I don't think they ever catch back up.  I 
> can remove the back log of "flows.*" and leave the "flows.current" until 
> the five minute change over.  I don't like doing this as then the graph 
> has a HUGE blank spot.  Anyone else ever have this problem?  If so, how 
> did you fix it?  If not, any suggestions where I can start looking? 
> Could this be due to a heavy data download?  We are graphing our 
> Internet edge router that can have over 90Meg a second worth of data.
> 
> The flows keep coming in, and they are incrementing.  They just are 
> being moved out of the /usr/local/arts/data/.../flows/ directory.
> 

Hi Scott, I haven't seen the problem first hand, but the FlowScan 
documentation notes the importance of the processing time for the 
stats.  It's critical that the processing time is less than the 
interval time between subsequent runs.  Quite simply, if you're 
processing every 5 minutes, but it takes longer than 5 minutes to 
process the stats, then you're in trouble!  Maybe you're gathering 
more stats now than a year ago?  I'd start by looking at increasing 
the performance of the PC.

Hope this helps,

-Martin

-- 
Expert carrier network traffic analysis and visualisation
http://www.networkintelligence.biz
xenaphobia: The fear of being beaten to a
pulp by a leather-clad, New Zealand woman