HPE Storage Users Group

Hi

Can anyone explain how the checkvv -dedup_dryrun does its Dedup Ratio calculations? For example, a recent analysis of one of our arrays shows: -

------(MB)------- (DedupRatio)
Id Name Usr Estimated Estimated

...

---------------------------------------------------------------
84 total 4578349 4051254 1.07


So 4.5TB dedups to 4TB, so divide Usr by Estimated and you get 1.13. However the tool shows 1.07.

Can anyone explain the discrepancy? Is there some other overhead that is incurred that the 1.07 is taking into account?

Thanks

There is always some capacity overhead with dedupe when you look at dedupe hashes etc. I've seen the same as you multiple times.

Either way, 1.1:1 in dedupe isn't really worth it, and I think best practices state something like 1.3:1 or 1.4:1 is the minimum you should consider.

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