Cluster Upgrade Strategy

[Ed Hall]

Folks,

I have some fairly basic questions about upgrading/expanding a existing
(less than 1 year old) Linux cluster with additional nodes. The cluster
is used in a University environment for both serial and parallel processing.

Is it better to buy older cpus that are the same as on the existing nodes
to keep the cluster homogenous so that its easier to administer and use?
Or does it make more sense to buy newer (and possibly fewer) cpus with
greater compute capacity at the expense of having a uniform set of nodes
in the cluster? If the only alternative is to buy newer nodes, should they
be used as a separate cluster rather than combining them with an existing
cluster of older nodes?

Thanks in advance for any advice you may have.

Ed Hall
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 Ed Hall                        Research Computing Support Group
 edhall at virginia.edu     http://www.itc.virginia.edu/researchers
 434-924-0620                             University of Virginia
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