Start by doing some reading, and then come back with questions:
Unified Communications in a Virtualized Environment
http://docwiki.cisco.com/wiki/Unified_Communications_Virtualization
can we install CUCM Version 9, Unity Version 9, CUPS version 8.0 in a single server?.
A: Review sizing chapter
For redundancy [ PUB + SUB ] we need to purchase two UCS server ?
A: Ideally, or you can use MCS servers for a node. You can have it on the same server if you still have horsepower but that's a single point of failure.
HTH
java
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www.cisco.com/go/pdihelpdesk
HTH
java
if this helps, please rate