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I've been doing some experimenting with Microsoft's new storage spaces but keep running into the same question.

I have a 2012 server with an HBA attaching it to two external disk array chassis. I've set the virtual disk sitting on top of the storage spaces to Mirror 2 and have set the IsEnclosureAware flag to true. The question I keep running into is now that even though the system is aware of the multiple chassis will mirrored data be split up among chassis as well as disks?

Benchmarking suggests mirror data is NOT necessarily spread across 2 chassis but I have not found any documentation from Microsoft or tests from other users confirming one or the other.

Has anyone seen any documentation on any of this or has experience with something similar?

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up vote 2 down vote accepted

Yes - if the IsEnclosureAware flag is TRUE, the virtual disk will attempt to use physical disks from different enclosures to balance the fault tolerance between two or more physical enclosures.

You can find this officially documented at:

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Exactly what I was looking for; Thank you. – R.K Dec 3 '12 at 15:30

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