ONTAP Discussions

Disappointing Storage Efficiency


I have a new AFF-A200.  I believe I've enabled compression...at least is says that it is enabled.  However I'm only getting a compression ratio of 1.3:1.  From what I've read and using the NetApp Active IQ analysis tool the average is around 4:1...why would this be occuring?



Enable other storage efficiencies like:

  • online compression
  • inline dedup
  • data compaction
  • offline dedup
  • offline compression
  • etc.


Note, you will not get much of storage efficiencies by magic if you placed on the storage data been already compressed or uncompressible data it would not show significant savings with:

  • pictures
  • video
  • audio
  • compressed data (Like NTFS compression)
  • compressed databases (Like Oracle DB compression)
  • encrypted data  (for example BitLocker)
  • etc.


You can read more about NetApp efficiencies in TR-4476 NetApp Data Compression, Deduplication, and Data Compaction.


You might be interested in the investigation of data misalignment between hosts & WAFL blocks which also may cause small efficiency gains.



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D_Berezenko thank you for the response.



I have double checked that I have inline and post processing compression turned on using this command


                volume efficiency modify -vserver vs1 -volume VolA -compression true -inline-compression true


Original volumes were not compressed before moving them.  They are coming from a NetApp FAS2440.


I have about 1.5 TB of Office (mostly Word), pdf, and email history files (Worldox) stored on a volume.  I expected to see a big compression advantage on this type of files.  The majority of the volume space is comprised of this data currently.  However, I'm getting 1.27:1 compression level for the volume.




Do not expect too much from Word & PDF documents.

Many documents contain images & other media information which is not compressable.



There is Storage Savings Estimation Tool which can determine what dedup ratio you should expect on ONTAP systems, but since you already have ONTAP, there is no need in SSE Tool.


Are you using NAS (CIFS/NFS) or SAN for storing your files?

If you are using SAN, check for misalignment.


Word files are pre-compressed unless they are in the old binary formats.  If they are small enough you may still see some reduction from data compaction.


Worldox is likely using at-rest encryption at the database file level, which minimizes the effectiveness of data efficiencies at the storage layer.



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