Replication Newbie Question

Hi,

Although I am very familiar with SAN concepts and design, I have no real experience in DR/replication so have a bit of a newbie question:

If one replicates LUNs from a primary to a secondary DC, how does one make use of them at the secondary site?

Say we had an exchange server in the primary DC with two LUNs presented from a SAN.  These LUNs host the Exchange DB and Log files.  Replication is configured to replicate these LUNs to a secondary DC.  Do I build a second Exchange server and have these LUNs presented to the server, but have the server shutdown during normal operations, and brought up only in the event of a disaster at the Primary DC?  If this is the case, does it have the same name at the Exchange server in the Primary DC?  How does Exchange handle this?  Do we need to use boot from SAN so that there is also an OS LUN that is replicated, therefore turning the server hardware into a "dumb head" for want of a better word?

Also, is it possible to make use of the LUNs in the Secondary DC in a read-only fashion so that we could run backups from these LUNs and not incurr a read penalty in the Primary DC?

As you can probably gather, I feel like I have an understanding block here, and would very much appreciate some expert guidance.

Cheers,

Phil