I would like to know what will happen in the following scenario:

1. Primary site: user maps to his home folder that sits in a cluster
resource that has Network Name DATA with IP address IP1

2. DR site: There is another cluster resource with Network Name DATA
but with IP address IP2

This means that DATA will have 2 entries in Active Directory DNS

If IP1 is not available, will the client automatically maps to IP2 or
does the DNS cache on the client needs to be flushed out before that
happens? Please advise. Thanks

"If IP1 is not available, will the client automatically maps to IP2"

There is no auto failover to a differernt ip address. For mapped drives you would want to use DFS so behind the scenes the "data" alias appears the same to the user but where it points now is physically different.

"does the DNS cache on the client needs to be flushed out before that? "

If on a DR site it is my understanding you would need to reboot the client for the connection to take place.

You appear to only be looking at ip which is the transport for getting to the servers/share. You need to look at the upper levels also.

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Kind of think you'd get a name resolution warning if you tried to make two computers named data no matter what the IP in the same domain.

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