Re: [Gzz] 25th, 26th, 27th & 28th (hh)

[hemppah]

Hi,

Quoting "B. Fallenstein" <address@hidden>:

> 
> Hi,
> 
> address@hidden schrieb:
> > Quoting Tuomas Lukka <address@hidden>:
> > > > > Does this work also with the "local store" model?
> > > >
> > > > What do you mean by "local store" (replication or something else) ?
> > >
> > > I mean: for each node, how much capacity should it allocate to the P2P
> > > network?
> > > I.e. if everyone has 50MB of P2P data that they *WANT* to store and
> > > allocate
> > > 2MB for data that the algorithm wants to store, what happens? Does only
> the
> > > 2MB
> > > get really used by others?
> > 
> > As far as I know, there is no limitation like this in DHTs (or in other
> > algorithms (?)).
> 
> A DHT stores mappings from keys to values. A node is allocated part of
> the key space; it must store all mappings that have keys in this key
> space. This is, indeed, limited by the local store. Let's take
> retrieving Storm blocks as a simple example; here, in the DHT, we store
> locations for each block, i.e., we have (block-id, peer-address) entries
> in the database. Let's assume that the block-ids are Storm IDs
> represented as strings (ca. 40 bytes/id) and peer-addresses are
> stringular representations of IP addresses and ports (ca. 20
> bytes/address). Rounding up to 64 bytes/item in the DHT, in 2MB, we can
> store about 2**14, i.e. roughly 16'000 items. If we assume 16 replicas
> for each item, a peer can insert about 1'000 entries into the DHT, i.e.
> it can publish 1'000 blocks.
> 

At first, I didn't understood the point which Tuomas was trying to tell me.
However, we discussed about this in the #gzz later today and I *finally*
understood the point ;).

Benja, good that you gave a concrete example. It seems that you have already
done some research on this topic :). In fact, how much have you (you and others)
 put effort on p2p and gzz ?

-Hermanni








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