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 Post subject: Dedup and Zero Detect
PostPosted: Thu Jul 19, 2018 6:42 am 

Joined: Wed May 07, 2014 1:51 am
Posts: 267
Hi,

is it ok and does it make any sense to enable both dedup and zero detect on the same volume? I thought that dedup is more or less a superset of zero detect and left zero detect off for dedup volumes, but apparently automatically created secondary volumes have both features enabled (both 3.2.2 and 3.3.1 do this).

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 Post subject: Re: Dedup and Zero Detect
PostPosted: Thu Jul 19, 2018 9:28 am 

Joined: Mon Sep 21, 2015 2:11 pm
Posts: 1570
Location: Europe
My understanding is that this is primarily which numbers you want to look good. Disable zero detect and the dedupe ratio will increase, enable zero detect and general compaction/thin ratio will increase.

Without zero detect, you will store a 16kB block with all zeros in th DDS, with zero detect on all volumes you don’t. To my knowledge no other AFAs support zero detect and will dedupe zero blocks to increase dedupe ratio and 3PAR does the same by default.

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 Post subject: Re: Dedup and Zero Detect
PostPosted: Wed Nov 20, 2019 10:35 am 

Joined: Tue Nov 19, 2019 10:32 am
Posts: 4
Just a small observation on latest firmwares:

Zero Detect option is always Enabled on newly created TTPVs.
Enabling Dedup superseeds Zero Detect and hides that advanced option.


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