Dell VNX8000 VNX2 Deduplication and Compression - Maximizing effective capacit - Page 8

In the above example, the deduplication process removes the duplicates of the original of 8 KB chunks. Consider a storage array which stores multiple copies of the same data. In this scenario, the array needlessly copies much of the data repeatedly. Deduplication consolidates most of the 8KB duplicate parts and releases additional space for other purposes. The VNX Block Deduplication Process VNX Block Deduplication is enabled on a per pool LUN basis. For LUNs that will use Block Deduplication, EMC recommended that deduplication be enabled at the time of LUN creation. Creating a deduplication-enabled LUN will create the LUN directly within the deduplication container. When enabling deduplication on an existing LUN, the LUN will be migrated into the deduplication container using a background process. The data must reside in the container before the deduplication process can run on the dataset. During this migration, the deduplication state for the LUN will show as enabling and the migration progress can be viewed on the Deduplication tab within the LUN Properties window. Once the migration is complete, the LUN will be Thin and deduplication is enabled. To enable deduplication on a Classic LUN, first create a deduplication-enabled LUN within a pool and use LUN Migration to migrate the data to it. For applications requiring consistent and predictable performance, EMC recommends using Thick LUNs. If Thin LUN performance is not acceptable, then do not use Block Deduplication. During a migration of a pool LUN either into the deduplication container or out of the deduplication container when deduplication is disabled on a LUN, the pool requires free space greater than 110% of the consumed capacity of the original LUN. Creating a LUN with deduplication enabled is suggested, as this will eliminate the migration and required overhead that comes with it. The deduplication container is private space within a pool in which all data for deduplication-enabled LUNs resides. This container is created when the first deduplication-enabled LUN is created, or deduplication is enabled on a LUN within a pool. The deduplication container is destroyed when deduplication is disabled on the last deduplicated LUN or when the LUN is deleted. There is only one deduplication container per storage pool. The total space used for the container depends directly on the amount of space used by the deduplicated LUNs. This space is not reserved when a pool is created, but rather is used when deduplicated LUNs exist. Non-deduplicated and deduplicated LUNs can coexist within the same pool. When a deduplication container is created, the SP owning the container needs to be determined. The container owner is matched to the Allocation Owner of the first deduplicated LUN within the pool. For example, if the Allocation Owner of the LUN is SPA, then the deduplication container will be created on SPA. Enabling Block Deduplication on subsequent LUNs will cause the Allocation Owner of the LUNs to match the owner of the deduplication container. When enabling deduplication on existing LUNs, the Default and Current Owners will be retained after deduplication is EMC VNX2 Deduplication and Compression 8