I read the white paper "Next Generation storage efficiency with EMC Isilon SmartDedupe". Looking over the best practices sections got me curious about two items:

1) "Avoid adding more than 10 subdirectory paths to the SmartDedupe configuration policy" -

My question is why ?  I service multiple customers where on the file system they are segregated into their own root directory, ie:

/ifs/clustername/customerA

/ifs/clustername/customerB

/ifs/clustername/customerC

...and so on

I could have close to 30 customer where some customers would benefit from Dedupe and others would not ..so enabling Dedupe at clustername is not going to work for me.

2) "EMC Isilon SmartQuotas accounts for deduplicated files as if they consumed both shared and unshared data. From the quota side, deduplicated files appear no differently than regular files to standard quota policies. However, if the quota is configured to include data protection overhead, the additional space used by the shadow store will not be accounted for by the quota"

I am trying to understand how dedupe will be reflected in quota numbers. Let's say i have a department that has 1TB quota directory. That directory is 50% full. Now i enabled dedupe on that directory and it gets deduped by 50%. What will i see when i look at my quota utilization, will i see 500G or will i see 250G ?  My goal is for my customer to see the benefits of me enabling Dedupe.

Thank you