To identify duplicates, data can be examined in different
ways depending on the technology used. For example, file-level dedupe—also
called single-instance storage(SIS)—will identify identical files, store a
single copy and replace subsequent identical copies with a pointer to the
unique version stored. Examples of file-level deduplication include Novell
Inc.’s GroupWise and Microsoft Corp.’s Exchange (although SIS isn’t supported
in Exchange 2010) email programs. EMC Corp. also provides file-level
deduplication on its storage arrays, including Clariion, Celerra and its new
VNX series.
