@Abdellatif AITELBACHA , that is my understanding as well. I’ll chat with some of our developers and get a response back on this thread.
Does your customer have Media Agents with hardware ready for commvault deduplication?
If not then answer will be go for appliance dedupe only. If answer if yes, according to Exagrid (https://www.exagrid.com/exagrid-products/supported-data-backup-applications/commvault/), both dedupe settings can be used, I guess in that case savings on the Exagrid side will not shine.
I have never configured Exagrid at a customer site, let us know how it goes.
Hi @Abdellatif AITELBACHA
I worked with one customer running Exagrid and SP’s are with dedupe. I see that you can use both but letting Exagrid do it has it’s own advantages.
https://www.exagrid.com/wp-content/uploads/ExaGrid-Commvault_DS.pdf
Thanks guys.
It is a new deployment so nothing already using CV dedup.
I am just confused between what Exagrid states on their data sheet when the say that we can use both CV and Exagrid dedup and “our” best practice when it comes to deduplication hardware. in the other hand they do mention that they have dedup ratio increase for long retention data (al least 18 weeks).
They also mention on another doc that the number of simultaneous streams must be kept low (less than 20) or face performance degradation. That seems to apply to dedup or no dedup.
I guess the only way to find out is to do a test, dedup SP vs non-dedup SP and see which performs best with various number of streams .
Disabling CV dedup will have impact on LAN and on DASH Full. DDB validation and verification jobs will also need to be tweaked so they do not use a maximum number of streams (assuming we enable CV dedup).
@Mike Struening : Please post any information or suggestion you may have from developers as I still have to design the solution for this project and really need to know Commvault position in this matter.
Thanks again
Abdel
@Abdellatif AITELBACHA , I’ll get them to reply directly here 
Guys
I received the attached document from Exagrid themselves.
Posting here if you ever encounter such setup
@Abdellatif AITELBACHA , that is such an awesome find!! I’ll mark your reply as the best answer. Thank you!!!