marcia-

here is another theory to throw out.  if you ran gmetad in the default 
configuration, it will create round-robin databases that expect to be 
updated every 15 seconds.  if after these databases where created, you 
changed the interval to be larger then you have a problem (unless you 
flush all the rrd databases a.k.a. rm -r /var/lib/ganglia/rrds).  rrd 
requires a heartbeat interval which in gmetad is

   heartbeat = 8*step;

that means that if the database is not updated in 8*15 secs (120 secs) 
then it will save a "NaN" record.  if greater the half of the records 
rrdtool averages over a "NaN" then a "NaN" is saved to the RRA 
(round-robin archive).

unfortunately, changing the step in a rrdtool is not handled dynamically 
in gmetad.  you might look at rrdtune commandline tool to tweak the 
databases if it's critical you keep the info.

-matt

Today, steven wagner wrote forth saying...

> From: steven wagner <[EMAIL PROTECTED]>
> To: Marcia Prescott <[EMAIL PROTECTED]>
> Cc: ganglia-general@lists.sourceforge.net
> Date: Fri, 01 Aug 2003 15:28:22 -0700
> Subject: Re: [Ganglia-general] Gmetad slowly collecting data
> 
> I have no answers, only vaguely-informed statements and half-formed 
> questions (welcome to free software's version of tech support!).
> 
> It is interesting to note that 4 hours = 16 real data points (at 
> 15-minute polling intervals).  That's a suspiciously round number...
> 
> However, if this was just a matter of the graphs not displaying because 
> there weren't enough interpolated data points to render a nice graph, I 
> would have expected them all to pop up at the same time...
> 
> At this point, I would want to compare gmetad's raw XML output to the 
> output of the monitoring core it's polling.  The polled monitoring core 
> should have a full metric payload.  If it doesn't, then you've got some 
> kind of multicast problem involving that node.  Compare its output to 
> the rest of the cluster, that may help.  Otherwise, crank up the debug 
> level and your favorite packet sniffer...
> 
> Assuming the monitoring core's OK, then the metadaemon's being funny. 
> What happens if you restart the metadaemon?  What happens if you change 
> the polling interval?
> 
> I shudder to recommend running gmetad with debug on for several hours 
> ... heck, I left it on for ten minutes once and it made me cry, but that 
> was on a few hundred nodes. :)  Unfortunately, that may be the only 
> thing that can offer you clues as to why it's taking so long for new 
> nodes to pop up.
> 
> gmetad should be walking straight through the <HOST> tags in the XML 
> parser.  Maybe there's something keeping it from finishing... assuming 
> the new hosts are at the bottom?
> 
> Just a few ideas for you.  Good luck!
> 
> Marcia Prescott wrote:
> > I've been using ganglia for a couple of months.  In
> > this time it has been great.  I set it up so that I
> > would gather the information at longer intervals of 15
> > minutes between polls.  This has been working great!
> > 
> > A couple of days ago, I started gmond on 30 nodes of a
> > cluster.  I was already monitoring 3 of those nodes. 
> > The data has been slow to join the summary
> > information. 
> > Could this be because I changed the polling intervals?
> >  
> > 
> > I would think that the nodes that I added would all
> > show up at the same time.  Instead, a new node joins
> > the summary information about every 4 hours.  Why is
> > this?  It is about every four hours that graphs appear
> > for the nodes, as well.  
> > 
> > I can see the graphical representation for all of the
> > nodes, but they lead to a page with no collected data
> > for the node.  
> > 
> > The XML data is sending the information for all of the
> > nodes, but the Gmetad doesn't seem to be collecting
> > the information as expected. Why does it take so long
> > to collect the data?
> > 
> > Thanks,
> > 
> > Marcia Prescott
> > 
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