Hi,
No, you don't have to present the Storage LUNs to the vCenter server (if installed on physical host). Its recommended that you have redundant network connectivity between the ESXi hosts and vCenter since that's how the heartbeat information is shared. In most of the installations vCenter is a VM and if that is what you have then you can srtike out this step of presenting LUNs to the vCenter VM. The storage is configured between the ESXi hosts and the LUNs and vCenter gives you a management interface to create/delete VMs on the underlying storage.
-Arun
https://twitter.com/arunpande
http://highoncloud.blogspot.in/
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