Indexing Changes Most Of The Blocks Of Database On Storage

DB: Oracle 10g R2
OS: SUSE Linux SP 1 x864

We are maintaining a DR of our Database Server(oracle 10g R2 atop SUSE SP1 Linux) using Platespin(

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Platespin is set to replicate(block based), incremental data(delta) every 1.5 hour from Production to DR site over a 30 Mbps dedicated fiber link.

Our maximum changes of data per day(during business hours) wont exceed 300 MB. During business hours Platespin replicates at least 1 GB at every replication cycle, while during off hours it replicates 300 to 500 MB per replication cycle. We are facing this strange issue with this box only(SLES 10 SP1 + Oracle 10g R2), we have protected MS Exchange 2007 Server based workloads without this strange issue, i.e in case of Exchange only delta replicates from Production server to DR site on Platespin.

Platespin support says us that Oracle re-indexes its database for better performance, so it is possible that re-indexing causes the blocks level changes on the storage, and since Platespin works on Block level, thats why it replicates so much(even though data is not changed that much)

here is actual words of Platespin support

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I think whenever Oracle database Indexing happens, it changes almost most of the Blocks of database and Platespin replicate all those Blocks.

As you know, Platespin checks the Date/Time attribute of every blocks before replication and if Date/Time attribute changes from last replication, it considers as changed block and replicate those blocks on Platespin Appliance. So, my suggestion is just look into the Oracle server behaviour before/after Data indexing process and do needful or do some workaround to overcome this issue.

</snip>

is there anything we can do at oracle level ?