Re: [DotGNU]Re: MOSIX as WOS

[Bill Lance]

--- Norbert Bollow <address@hidden> wrote:
> > Bill Lance wrote:
> > > 
> > > how does this translate into a useful p2p
> > > environment?
> 
> Let me quickly note that indeed it makes perfect
> sense to
> discuss 2p2 systems in the context of webservices
> which are by
> definition client-server applications.  On one hand
> the
> client-server stuff can be built upon a p2p system;
> on the other
> hand you may want to have multiple servers that
> communicate wirh
> each other through a p2p system.

The question did not relate to the relevance between
p2p and webservices.  It asked the relevance of MOSIX
to p2p.  MOSIX is essentially and cluster environment
with an empahsis on load balancing, as disticnt from
the parralle processing focus of BEOWuLF.  It will
move certain linux processes to other CPU's on the
network for execution, returning the output of the
process to the originating machine.  It will not
migrate certain processes, especially those processes
using hardware specific i/o ports.

Actually, the os's, and any applications running on
the two machines, are not communicating with eachother
at all.  The host machine is just loaning out CPU
cycles and some memory for the time being.  It has no
idea at all of what those resoruces are being used
for.



> 
> David Nicol <address@hidden> replied: 
> > define "useful"
> 
> In the context of webservices, I would say in order
> to be
> useful, the system must be able to support
> 
> * load balancing between multiple server nodes
> 
> * smooth handling of, and recovering from a "network
> split" in
>   which the networked system is temporarily split
> into two
>   systems which are incapable of communicating with
> each other,
>   but which both provide the netservice to clients
> during the
>   split.
> 
> 
> My main questions about MOSIX are:
> 
> 1. Is MOSIX only about making use of the CPUs of
> multiple nodes,
>    or is it also about making good use of the
> network
>    connections between those nodes and the outside
> world?
> 

See above.  They can not share i/o ports.


> 2. For purposes of creating a distributed system for
> providing
>    webservices, does it really make sense to do it
> by means of
>    kernel patches?
> 
>    (I've always been thinking of WOS as a system
> consisting of
>    sysadmin tools and middleware, all of which would
> run
>    completely in userspace within the DotGNU Secure
> Execution
>    Environment.)
> 


Exactly.  The MOSIX patched kernel creates in effect,
a vurtual CPU, not a network.  It is useful only where
some network nodes are CPU bound by multiple
processes.  Also, it can not split a process (it does
NOT migrate threads, just processes not connected to
any I/O ports).  


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