Hi Truffer,

> Message-ID: <[EMAIL PROTECTED]>
> From: Pub <[EMAIL PROTECTED]>
> Date: Wed, 09 Jan 2008 10:08:41 +0100

> I'm currently testing different DHT implementations (P-Grid, Bamboo, ...) and 
> I realized that all these DHTs are good only for a large amount of nodes with 
> a small number of keys per node. In fact, I'm looking for the opposite: a DHT 
> able to deal with millions of keys per node, with a few number of node (let's 
> say 100).

How about those you investigated?

I have an experience that nodes go down when I put a number of
key-value pairs in a DHT implementation. With the implementation, only
3000 items overflow from a node with 32 MB of heap in a Java VM.

The amount of heap is a promising candidate for a bottleneck. I guess
it is common for DHT implementations not to limit the number of items
a node can hold and go down when many items are put. Large heap will
extend the limit.

> Do you know such DHTs (I would like real numbers if possible, and not "it 
> should work" answers) ?

I have put 10,000 items in a node running Overlay Weaver, a
DHT implementation which supports multiple routing algorithms.
But I have not tried to put a massive number of items.


> In the same topic, are there working DHTs that focus on response time (eg 99% 
> of replies < 200ms) ? For example, is there any academic project going into 
> the direction of Amazon's Dynamo ?

DHT Access Tools include benchmarking tools to measure such response time.

  DHT Access Tools (available on Overlay Weaver web site)
  http://overlayweaver.sf.net/

It can access to a DHT running Overlay Weaver or Bamboo with XML-RPC.

  OpenDHT: A Publicly Accessible DHT Service (Bamboo nodes on PlanetLab)
  http://opendht.org/

  Overlay Weaver nodes on PlanetLab
  http://www.google.com/search?hl=ja&q="Overlay+Weaver+Node"&filter=0

I have measured performance of Overlay Weaver and Bamboo and noticed
that other operations (e.g. XML processing) than DHT operations took a
large part of the measured time.

Anyway, roughly saying, 10000 times of get took from 25 sec to 100 sec
with a moderate PC or 5 PCs running Overlay Weaver or Bamboo on a LAN.

Thanks,


  Kazuyuki Shudo        [EMAIL PROTECTED]               http://www.shudo.net/
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