Oracle and volume- and disk array-based replication?

Dear mighty all,
here is a situation:
Location A - active Oracle database + volume replication software + geocluster software
Location B - standby location, i.e. standby database + volume replication software + geocluster
Oracle is 10g
The size of the database is 500 GB+
The daily updates are roughly 2-3%.
The comm channel between locations can have any reasonable bandwidth, however the jitter and latency cannot be guaranteed (i.e. no synchronous replication).
This is a matter of protecting against a disaster (such as a complete destruction of Location A).
The task is to make sure that Location B has the up-to-date data (RPO is 8 hours) and Oracle database can be started automatcially without any manual intervention. (I.e. cluster administrator pushes the button and the rest is done without human intervention).
Here is what I am thinking of:
1) volume replication software usually observes the atomicity on the disk block level. I.e. it is impossible that the data block being updated on the volume in Location A is updated in location B incompletely.
2) When the database in Location A completes a transaction it writes data to the disk thus initiating the series of disk block updates being sent to Location B.
3) From the database point of view, the transaction is completed, database files are updated.
4) However there is a slim chance of Location A being destroyed while:
* the volume replication software has started pushing through to Location B the updated disk blocks representing the completed transaction
* but it did not finish transmitting the whole lot of disk updates (boom! the asteroid fell on Location A)
* and volume replicator in Location B cannot roll back the disk updates since volume replicator does not know of the database transaction
5) Volume replicator atomicity is disk data block while Oracle's atomictity is transaction (i.e. there cannot be a half-transaction applied)
6) Thus, when we start Oracle in Location B, we will get inconsistent database, since the last transaction was transferred to Location B incompletely
7) Sure that there is a way to fix this using various DBA tools, but that defies the whole purpose of automatic start
So, my question is:
1) Is volume- or disk array-based replication not a good idea in this case at all?
2) or is there a way to nonetheless ensure the consistency of the database (say start it every time in the recovery mode)?
3) Or should I dump the idea of replicating Oracle with volume replication and switch to DataGuard? (The cluster software can handle DataGuard).
thanks a million for your answers, ye mighty all!

Hi,
this is not a "typical" question what is easy to discuss in a forum.
Just some hints:
1. using volume replication won't help you against logical or physical corruption
2. RPO of 8 hours ? Sounds a lot regarding a change rate of 10-15 GB a day.
3. 100% Automation is normally not a good idea in a database disaster scenario
( a false disaster detection can end in a real disaster!) I've already seen too much databases which had been totally corrupted by a false switch.

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