[p2p-hackers] Re: scalability

[Adam Fisk]

I don't understand your post.  When you say "critical", I assume you're 
talking about life and death situations?  Are you talking about anything 
specifically?  DHTs have failure rates.  Ad hoc and mesh networks can 
become useful in emergency situations where conventional infrastructures 
break down, but the centralized/p2p/structured/unstructured questions 
here are far from obvious.

On the "obsessive science types" issue, this completely misses the 
point.  It's a very non "obsessive science type" statement.  There are 
strong reasons for using the massive indexing/random walk approach above 
DHTs -- reasons that have nothing to do with scalability.  In 
particulary, DHTs are, well, hash tables.  Hash tables don't work well 
for metadata queries.  They do fine for keywords (hotspots are a 
problem, but they can be solved), but they aren't as nice a fit for 
metadata.  RDF and DHTs are tough to squeeze together, for example.  The 
massive indexing (mutual index caching to use Serguei's term)/random 
walk approach can get around these issues more easily.  They are also 
not nearly as brittle as DHTs.  Sure, DHTs repair themselves after node 
joins and leaves, but node transience generally has a much greater 
effect on DHTs than it does on massive indexing networks.

I also think you're underestimating the efficiency of massive indexing 
and random walks.  Sure, these networks don't scale logarithmically, but 
they do pretty darn well. 

I encourage everyone to stay specific with their posts.

All the Best,

Adam


Ronald Wertlen wrote:

> Hi,
>
> Gnutella-bashing certainly may be fun, the truth is, it is 
> tremendously well-adapted for its purpose (I think Serguei's said the 
> relevant stuff).
>
> However, I also believe it is pretty clear that from a search point of 
> view, a random super-peer based network does not scale - it is never 
> going to get the kind of precision and recall that we would call 
> intelligent. It would be too slow or too inaccurate.
>
> (This belief may be substantiated by looking at one of the best search 
> and retrieval super-peer networks we know - our brains (menufactured 
> by millenia of evolution or a master craftsman ;-)) - and that's 
> certainly not randomly structured, although parts of it probably are.)
>
> To sum up some: Gnutella is great in a non-critical scenario, but 
> sucks for obsessive science types.  ;-)
>
> best wishes, Ron
>
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