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Data reduction techniques
Vendors have deployed a number of space-reduction techniques, some of which have been available for a while, and others that are new to primary storage platforms. The key data reduction technologies include thin provisioning, compression and data deduplication.
Thin provisioning is already widely implemented by all the major storage array vendors and is pushing down into midmarket and even small office/home office (SOHO) devices. The technology works by eliminating the reserve on unwritten blocks of storage, allowing overprovisioning of storage resources and enabling more logical capacity to be created than is physically available. However,
Compression is a space-reduction technique that looks to optimize the data stream by finding repeated patterns of similar information that can be reduced and replaced with an optimized data structure. The compression process is usually performed in-flight as the host writes data. The technology has been around for some time and was in use as long as 25 years ago in IBM tape drives.
Data deduplication (or dedupe) looks for repeated patterns of data, usually based on a fixed block size, and reduces them to a single physical instance of the pattern. All references to that block of data then point to the single physical copy. As data is changed, the resulting updates have to be stored elsewhere in the array as a new copy of that data.
This was first published in October 2012