Re: inventory

[Peter Badovinatz <tabmowzo@yahoo.com>]

--- Greg Lindahl <lindahl@conservativecomputer.com> wrote:
> On Wed, Feb 28, 2001 at 02:36:33PM -0800, Peter Badovinatz wrote:
> 
> > I would love to see 'one way' to set/read the node number.
> 
> What's a "node number" for? In the clusters I've built, nodes have
> unique names, which happen to be the Unix hostname. Is that not
> appropriate for your use?

A node name is a lot of data to send around and to maintain for cluster
components.  One 'complaint' we get is that our messages/memory/etc. take up
too much bandwidth as it is.  We often have to send around "maps" of all of the
nodes that are in the cluster as part of membership consensus decisions, so
sending the actual hostnames gets relatively large, especially as our code
usually does its main work during failure events, when the networks are often
flaky.

We can generate maps of nodes using the names, but we still have to agree as to
the positions or layout.  We also usually support (in fact usually demand to
eliminate single points of failure) each node have multiple network
connections, and multiple names, so a single hostname is not sufficient for us.
 We also tend to move IP addresses around (one of the jobs for which we get
paid!)  A node number makes it easier to uniquely refer to "a node" in these
cases, but, yes, it is a matter of sructure, degree and philosophy.

One other point is that most existing commercial HA clustering uses node
numbers, and if we're porting that, we use node numbers.
> 
> -- g
> 


=====
These have been the opinions of:
Peter R. Badovinatz -- (503)578-5530 (TL 775)
wombat@us.ibm.com/tabmowzo@yahoo.com
and in no way should be construed as official opinion of 
IBM, Corp.

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