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Dell Unity Data Reduction through compression is available for Block LUNs and VMFS datastores in an all-Flash pool starting with Dell UnityOS 4.1. Data reduction via compression is available for file systems and NFS datastores in an all-Flash pool starting with Dell UnityOS 4.2. Beginning with Dell UnityOS 4.3, data reduction includes both compression and deduplication. As of UnityOS 5.2, data reduction can be enabled on hybrid; A hybrid pool must have at least 10% Flash capacity to enable data reduction.
Be aware that data reduction increases the overall CPU load on the system when storage objects service reads or writes of reduceable data and may increase latency. Before enabling data reduction on a storage object, it is recommended to monitor the system and ensure that the system has available resources to support data reduction (refer to the Hardware Capability Guidelines section, Table 2). Enable data reduction on a few storage objects at a time, and then monitor the system to be sure it is still within recommended operating ranges, before enabling data reduction on more storage objects.
For new storage objects, or storage objects that will be populated by migrating data from another source, it is recommended to create the storage object with data reduction enabled, before writing any data. This provides maximum space savings with minimal system impact.
Dell Unity Advanced Deduplication is an optional extension to Data Reduction, that can be enabled to increase the capacity efficiency of data reduction enabled storage objects. Advanced deduplication is not available on all models. For information on which systems can enable advanced deduplication, please refer to the Dell Unity: Data Reduction white paper available on Dell Support.
As with data reduction, advanced deduplication is only applied to data when it is written to the storage object. LUN Move can be utilized to deduplicate existing data on Block storage objects.
For new storage objects, or storage objects that will be populated by migrating data from another source, it is recommended to create the storage object with advanced deduplication enabled, before writing any data. This provides maximum space savings with minimal system impact.