PSINet/Cogent Latency

Tue Jul 23 06:47:52 UTC 2002

On Mon, Jul 22, 2002 at 11:42:57PM -0700, Gary E. Miller wrote:
> 
> Yo Alexander!
> 
> On Tue, 23 Jul 2002, Alexander Koch wrote:
> 
> > imagine some four routers dying or not answering queries,
> > you will see the poll script give you timeout after timeout
> > after timeout and with some 50 to 100 routers and the
> > respective interfaces you see mrtg choke badly, losing data.
> 
> Yep.  Anything gets behind and it all gets behind.
> 
> That is why we run multiple copies of MRTG.  That way polling for one set
> of hosts does not have to wait for another set.  If one set is timing
> out the other just keeps on as usual.

Parallelism is polling science 101. If your poller can't do this, it will 
never scale, just give up and go home.

And I mean controlled parallelism, not forking out all your queries at
once and letting the system sort it out (as I've seen done by people
waving their redhat cds and perl tshirts).

-- 
Richard A Steenbergen <ras at e-gerbil.net>       http://www.e-gerbil.net/ras
PGP Key ID: 0x138EA177  (67 29 D7 BC E8 18 3E DA  B2 46 B3 D8 14 36 FE B6)