[clug-talk] Newbie Clustering Question

[Mark Lane]

On 10/7/05, Shawn <sgrover at open2space.com> wrote:
>
>
> After the presentation last night, I did some cursory digging into
> openMosix,
> and have a couple of questions.
>
> As I understand things, I *should* be able to setup my primary server as
> the
> head node, and then join my secondary servers/workstations into the
> cluster.
> But, I'm curious if this would be worth the effort (from an learning
> perspective, rather than a technical perspective).


You can do a lot with a Mosix cluster. Mosix will attempt to move execution
processes to the lower load systems.
It will allow you to send processors to specific systems. Move processes
from one system to another all in the management.
I have never tried it but I am pretty sure while you are running mosix on a
client workstation, it can still be used as a workstation.

My primary server is a dual PIII-500, which currently provides file sharing,
> web, email and database services. Does it make sense to set this up as a
> head node when at some times it would be the ONLY node?


I don't know that you will get a significant advantage running mosix but it
may be a good experiment. As I understand it, Apache or at least older
versions of apache do not lend themselves to process migration. As such you
would mostly be looking at maybe some database processes and the like. I am
not clear on the apache issue as I learned about it from a clustering book I
am reviewing and I haven't found the book factually accurate in other areas.

As for running as only one node sure, it should do that fine. Just migrate
your processes back to the main server.

I'd like to add my
> desktop computers into the node when they're being used, but still keep
> them
> available for regular use.


That should be possible.

I don't see yet why this shouldn't be possible,
> but can someone elaborate a little for me? (I do have a second server, but
> was planning on migrating the databases there to the primary and shutting
> it
> down).


You would probably want to use the web interface to add and subtract the
desktops as you want them.

Then, I have a bit of a concern on what happens when I shut down the
> desktop.
> I'm assuming the usual clustering activites kick in, and overall things
> just
> keep working. But is there a danger if the cluster collapses to a single
> node?


Well I don't think you want to be shutting down a desktop without having all
the mosix processes migrated off. Now mosix is used in some high
availability networks so it should have some allowances for dealing with
failed nodes.

--
Mark Lane, CET <lmlane at gmail.com>
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