[Beowulf] recommendations for a good ethernet switch for connecting ~300 compute nodes

[Rahul Nabar]

On Wed, Sep 2, 2009 at 11:15 PM, Joe
Landman<landman at scalableinformatics.com> wrote:
> Rahul Nabar wrote:

> For a cluster of this size, divide and conquer.  Head node to handle cluster
> admin.  Create login nodes for users to access to handle builds, job
> submission, etc.

> Hmmm... We don't recommend burdening the head node with storage apart for
> very small clusters, where it is a bit more cost effective.

Thanks Joe! My total number of users is relatively small. ~50 with
rarely more than 20 concurrent logged in users. Of course, each user
might have multiple shell sessions.

So the experts would recommend three separate central nodes?

Loginnode
Management node (dhcp / schedulers etc.)
Storage node

Or more?

> Depending upon how your nodes do IO for your jobs, this will dictate how you
> need your IO designed.  If all nodes will do IO, then you need something
> that can handle *huge* transients from time to time.  If one node does IO,
> you need just a good fast connection.  Is GbE enough?  How much IO are we
> talking about?

I did my economics and on the compute nodes I am stuck to GbE nothing
more. If this becomes a totally unworkable proposition I'll be forced
to split into smaller clusters. 10GbE, Myrinet, Infiniband just do not
make economic sense for us. On the central nodes, though, I can afford
to have better interconnects. Should I? Of what type?


-- 
Rahul