Dear Sir, I am writing to thank you for your letter and say,
On Wed, Feb 11, 2004 at 11:29:59PM +0100, Grilli, Laurent wrote: > Dear Burton, > > > Looking to the back traffic on ntop, ntop dev, i found few articles about > memory (old version of ntop) more about memory leak,...and also the use of > the switch -C for disabling feature (for a user with 256 Mb) > .. snip .. > > So is it possible for people to tell me some tips/guidelines, i know that > it's not so evident as it depends of the topology, number of hosts, > traffic...peak, average use of the bandwidth. I'm going to upgrade anyway > this box to a bi xeon with 2 gb of memory but would it be enough... > This part of the docs/FAQ may help ' Q. So ntop's memory usage is dependent upon? A. ntop's memory usage for host tables depends on the # of hosts it sees in packet traffic. This is NOT, repeat NOT controllable by ntop in ANY way. If a user kicks off a port scan, 100s of hosts appear. If somebody does a DOS attack against you, 1000s of hosts 'appear'. If a user searches Kazza for an obscure song, it can probe 4K hosts. etc. Lots of those hosts appear, have a few bytes of traffic and then disappear. Each host has a variable amount of memory - there's a base structure, some optional counter structures and a large # of pointer fields, which may or may not be valued for any given host. It depends on the # of active sessions and a lot of other things, but 8-20K is a good guess - I usually use 12K as an guestimating size. Similarly, sessions may appear and disappear (http: opens a lot, does a small retrieval and closes them), ssh may last for days. etc. Memory is consumed tracking them too. ' One of Mr Strauss's cracker of a letter (meaning full of information) about memory speed and usage dealt with ntop performance factors and the critical nature of high speed memory. Of course I can't find it now. The bit in the FAQ item that concludes 'The moral is that if you're going to use ntop to monitor big fat links, you need screaming fast iron.' Yours sincerely. > Thanks in advance > Laurent Grilli Yours sincerely. -- ------------------------------------------------------------------------ Stanley Hopcroft ------------------------------------------------------------------------ '...No man is an island, entire of itself; every man is a piece of the continent, a part of the main. If a clod be washed away by the sea, Europe is the less, as well as if a promontory were, as well as if a manor of thy friend's or of thine own were. Any man's death diminishes me, because I am involved in mankind; and therefore never send to know for whom the bell tolls; it tolls for thee...' from Meditation 17, J Donne. _______________________________________________ Ntop mailing list [EMAIL PROTECTED] http://listgateway.unipi.it/mailman/listinfo/ntop
