Guidelines for using deduplication

You must remember certain guidelines about system resources and free space when using deduplication.

•	If you have a performance sensitive solution, carefully consider the performance impact of deduplication and measure the impact in a test setup before deploying deduplication.

•	Use the Data ONTAP version 7.3. Deduplication requires at a minimum ONTAP 7.2.5.1, but ONTAP 7.3 is recommended.

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Deduplication is a background process that consumes system resources while it is running. If the data does not change very often in a FlexVol volume, it is best to run deduplication less frequently. Multiple concurrent deduplication operations running on a storage system lead to a higher consumption of system resources.

•	You must ensure that sufficient free space exists for deduplication metadata in the volumes and aggregates.

•	For releases earlier than Data ONTAP 8.1, you cannot increase the size of a volume that contains deduplicated data beyond the maximum supported size limit, either manually or by using the autogrow option.

•	For releases earlier than Data ONTAP 8.1, you cannot enable deduplication on a volume if it is larger than the maximum volume size. However, you can enable deduplication on a volume after reducing its size within the supported size limits.

•	If deduplication is used on the source volume, use deduplication on the destination volume.

•	Use automatic mode when possible so deduplication runs only when significant additional data has been written to each flexible volume.

•	Run deduplication before creating a Snapshot copy to obtain maximum savings.

•	Set the Snapshot reserve for greater than 0 if Snapshot copies are used.