XML DB Questions..

Environment:
Oracle RAC 11.2.x on Oracle Enterprise Linux.

We are building a new application which needs to store XML data in the database. This database would be between 15-20TB in size, with 99.999% availability requirement..

I have been looking at the documents that compare between storing it as a CLOB vs XMLType. http://docs.oracle.com/cd/B28359_01/appdev.111/b28369/xdb01int.htm#BABBADBF

I am leaning towards Binary XML storage due to its flexibility and ease of data access through SQL, compact storage and high throughput.

A few questions:

1. To use XMLType would I have to use XML DB feature? Is there active development going on around this product?
2. What considerations would I have to take into account from Database Management perspective? How easy or complex is it from Database administration perspective?
3. Are there any restrictions/limitations to use it with EE options like Data Guard, Active Data guard, ASO, Tuning/Diag/Change management packs, Golden Gate etc.
4. Multiple applications may be accessing the data, so I like the idea of accessing the data through XQuery etc. Are there any concurrency related issues?
5. Are there any other design considerations that I'd have to account?

Thanks much in advance
Upendra                                                

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