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Can I achieve the same deduplication rate on a FlexGroup compared to a FlexVol?

Last Updated:


Applies to

  • ONTAP 9.8
  • FlexGroup
  • Storage Efficiency


No. Deduplication is done within FlexGroup constituents and not across the FlexGroup.

For example, the same file could be stored twice in the FlexGroup but on two different constituents – which means no deduplication will occur. FlexGroups will have a lower savings rate when large files are spread out over multiple constituents compared to FlexVol volumes.



There are four 100GB files in a FlexVol set up in the system:

Volume Filename Logical size
vol1 file1 100GB
vol1 file2 100GB
vol1 file3 100GB
vol1 file4 100GB

Because of deduplication working on the entire volume, they would take up:

Filename Physical size (deduplication of files) Logical size
file1, file2, file3, file4 100GB 400GB

Above will give us a 3:1 savings ratio.



In a FlexGroup, the files get split into multiple constituents:

Constituent Filename Logical size
Const001: aggr1 file1 100GB
Const001: aggr1 file2 100GB
Const002: aggr1 file3 100GB
Const002: aggr1 file4 100GB

Now the deduplication is working on each individual constituent: 

Constituent Physical size Logical size
Const001: aggr1 100GB 200GB
Const002: aggr1 100GB 200GB

The combined physical size would in the above example be 200GB, as the deduplication is not done across constituents, giving us a 2:1 savings ratio.

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