Re: available resource declaration language(s)

[David Santo Orcero <irbis@orcero.org>]

 Hello, David!

> > something like these scale well. If you have only one token, you have some
> > technical problems.
> 
> The technical problems are not insurmountable.  Who said the virtual ring
> must have only one token, or there must be only one virtual ring?

 The problem is on the physical layer and on the link layer, I was talking
about colitions. Using a virtual ring is not going to help you too
much, because... err... is virtual. I tried this to comunicate
subpopulations on a GA -once again, is sw at user level, but it does no
difference for the physical layer of the network- and you have that kind
of problems. And with two tokens things could be worst if one token run
faster than the another. Yes, it is possible: the two tockens runs at the
same velocity on the media, but you have also the delay on the propagation
on the nodes. If a node is working and delays to forward the package, you
will hace a colition, and the two tockens will be lost.

> like, if you need a resource and you have not received a token recently
> you send out a token.  The implementation of a robust token ring architecture
> is not only tractable, but well documented.

 Yes, I know. They are so well documented that I have to study on my
degree that protocols, and they are not trivial. You will have to
implement nearly the full 802.5 over UDP to do this work, and this is not
an easy work. Please, dowload and read the full IEEE 802.5 before
continuing this discusion.

> if the route of the token can alter, or fall back on p2p methods, there can
> be error recovery

 It is not so easy. Read a token ring protocoll.

> so the network divides into teams of ten, based on subnet (I hope all 500
> nodes are not on the same LAN segment) and a token is passed w/in each team,
> and the team spontaneously elects a Decurion to present the team to the other
> 49 Decurions, via p2p or virtual token ring architecture at that
>level.

 Yes, I supose that hobody has 500 nodes on the same LAN segment, basicaly
because it is not possible on the most of the networks -there are
limitations on the maximun size of a network cable for ethernet, and
a minimum distance between the nodes; it is not theoretical, test it-.

 There is only one problem on your solution: you can not
say to a user : "hey, guy, if you wanna use linux for clustering you gotta
use this topology". Basically, because not allways the guy that is
instaling Linux have enouth power to recableate all the non-dedicated
nodes.

 Anyway, yo work with Legion, isn't it?

> Broadcast scales better than p2p -- it is p2p that floods a large network.

 :-?

 Where do you take that piece of information? p2p really floods a
network? I thing that you are talking about Gnutella. Gnutella does not
scalle well, but it is not a problem of the p2p part. The problem is that
it broadcast the information of the songs. What it worst, really do not
use the IP broadcast facilities; it use a flooding algorithm to broadcast
the information of the query of the songs. And if you use a flooding
algorithm, you flood the network.

 p2p protocols are those involving the connection of two peers only. That
is why they scale well because err... the involve only two peers. They
have problems, that have been put here and does them unsuitable for HA,
but I cann't understand where is the problem on flooding. Maybe you have
hearing some about Gnutella, but it is not a p2p problem, the problem is
using a flooding algorithm to transmit information.

> Rings and broadcasts both scale better than peer-to-peer, because there
> is less redundant information streaming around. 


 8-O


 I am not going to discuss this. Test it. Then we discuss.

 Yours:

David


 
---------------------
http://www.orcero.org
  irbis@orcero.org
---------------------


Linux-cluster: generic cluster infrastructure for Linux
Archive:       http://mail.nl.linux.org/linux-cluster/