Learn the reasons why you should Deduplicate everywhere to get the most out of your IT. Symantec’s latest release of NetBackup 7 comes with Deduplication software already installed, making one of the things you need most right where you want it. Joe Pfeiffer (Product Manager with NetBackup) will take you through all you need to know about this great feature:
Data deduplication is a specific form of compression where redundant data is eliminated, typically to improve storage utilization. In the deduplication process, duplicate data is deleted, leaving only one copy of the data to be stored. However, indexing of all data is still retained should that data ever be required.
Deduplication is able to reduce the required storage capacity since only the unique data is stored. For example, a typical email system might contain 100 instances of the same one megabyte (MB) file attachment. If the email platform is backed up or archived, all 100 instances are saved, requiring 100 MB storage space. With data deduplication, only one instance of the attachment is actually stored; each subsequent instance is just referenced back to the one saved copy. In this example, a 100 MB storage demand could be reduced to only 1 MB. Different applications have different levels of data redundancy. Backup applications generally benefit the most from de-duplication due to the nature of repeated full backups of an existing file system (Wikipedia).
Sorry, but this article is wrong. What you are referring to is Single Instance store. Exchange has this built-in and backup software has this feature also. Deduplication is a combination of single instance store and incremental changes at the bit level.