[Beowulf] Re: MOSIX2

Vincent Diepeveen diep at xs4all.nl
Wed Oct 1 14:22:57 EDT 2008


Well Tony,

Things are pretty simple for using SSI at your beowulf cluster.

The short summary:

a) openmosix is dead
b) open-ssi is still alive

Simple tip: go for open-ssi.



A bit longer explanation:

a) openmosix is dead. I can confirm that even wikipedia has that.
      Openmosix was an Israeli project and therefore died when It's  
Israeli main developer left, for whatever reason.
       He has left a very clear statement that he no longer works on  
openmosix.
      What usually happens is that 1 or 2 enthusiasts then do an  
effort to support it. If that doesn't work for you,
      then consider it dead.

Using kernels 2.4.x is not realistic for todays quadcores. That was  
the status in 2005, that is in 2008 still the status.
In 2005 if i remember well i used kernel 2.6.7 for a quad opteron  
dual core.
Using kernel 2.4.x versus 2.6.x numa gave at a dual opteron dual core  
a speedloss of 50% for my chessproggie.
50% is *a lot* to lose in speed.

Supporting a thing like openmosix requires a lot more than 1 guy who  
in order to modify 3 bytes needs 1000 dollar.

What you see a lot is that open source projects get hijacked by  
people who want to make cash out of it.
In the world i come from, computerchess, i remember already since  
1988 that this happens every year several
times. The developers usually get really demotivated when they work  
for hundreds of hours at their 'money project',
and then just make under a 1000 dollar; at the macdonalds you make  
more money.

In short such projects usually die soon also, as there is no money  
for them into it. Most nerds are social seen total robots.

b) open-ssi is there fore several distributions and actively  
supported by several developers.
It is there, it works, it improves and it works for latest kernels  
also (yes also 2.6.x).

In itself it would be GREAT if there is 1 open source project there,  
as that joins forces more. My hope is that open-ssi
will work great for highend nic's also and slowly get to a phase that  
all features work great.

OpenMosix nor openssi could migrate processes that work with shared  
memory, a nerd feature i like personally a lot.

Just claiming that they use 'stolen' features like page migration is  
like claiming that linux stole multithreading from unix;
it is a bad attempt to smear dirt just to earn a 1000 dollar.

It is not a reason to not use it. It is a bad attempt to spit at  
these guys who donate time and their money without asking for payment.

Vincent


On Oct 1, 2008, at 1:10 PM, Tony Travis wrote:

> Vincent Diepeveen wrote:
>> I agree tony that paying for such crap is not very good idea.
>
> Hello, Vincent.
>
> I don't think MOSIX2 is crap!
>
> However, I don't like the idea of having to pay for 'updates'.
>
>> You might want to move to open-ssi in this case; the project is  
>> alive and there is in theory work getting
>> performed on support for cards over infiniband as well.
>
> I have looked at OpenSSI, which uses the openMosix load-balancer,  
> but process migration is more coarsely grained than in openMosix.  
> Only the active pages of the user context of openMosix processes  
> are migrated.
>
> I've been looking at alternatives and I think Kerrighed looks very  
> promising but, in our hands, Kerrighed is very fragile: I've  
> mentioned on this list before that if one Kerrighed node goes down  
> you lose the entire cluster. We've been talking to Christine  
> Morin's group at INRIA and they tell us that the next release of  
> Kerrighed with be more robust:
>
> 	http://www.kerrighed.org
>
>> Most importantly is that you are gonna get more replies.
>
> Yes, thanks for yours :-)
>
>> Additionally the manner open-ssi implements shared memory is very  
>> transparant; in principle on each write it migrates a page
>> to the node writing.
>> Maybe the only big lack of open-ssi is its limited support so far  
>> for highend network cards.
>
> What bothers me about OpenSSI is that it's based on an open-sourced  
> version HP's (now Compaq) discontinued commercial product "non-stop  
> clusters for Unix". The OpenSSI project also came in for a lot of  
> criticism from the openMosix community for stealing ideas, so my  
> concerns about it might not be all that well founded ;-)
>
> The main reason I didn't use OpenSSI, previously, was that many  
> features had not been implemented fully and, like Kerrighed, it  
> wasn't really a viable option for a 'production' cluster even  
> though it was interesting as a research project. What makes me take  
> MOSIX2 seriously now is that it is a commercially supported  
> 'product' with all the same virtues (and most of the vices) of  
> openMosix.
>
> 	Tony.
> -- 
> Dr. A.J.Travis, University of Aberdeen, Rowett Institute of Nutrition
> and Health, Greenburn Road, Bucksburn, Aberdeen AB21 9SB, Scotland, UK
> tel +44(0)1224 712751, fax +44(0)1224 716687, http://www.rowett.ac.uk
> mailto:ajt at rri.sari.ac.uk, http://bioinformatics.rri.sari.ac.uk/~ajt
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