Data Reduction; Data Deduplication; Compression; Space Reclamation - Quantum DXi6900 User Manual

Chapter 1: System Description

Data Reduction

Data Reduction

Data reduction is the process of reducing the amount of storage capacity required to store your data. The
DXi6900 systems provide two techniques to optimize the storage space required on your system:
Data Deduplication below
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Compression below
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Data Deduplication

The DXi-Series disk backup and replication systems use Quantum's patented data deduplication technology
to dramatically increase the role that disk can play in data protection. With DXi-Series solutions, users can
retain 10 to 50 times more backup data on fast recovery disk than with conventional arrays. This advantage
allows IT departments to cost-effectively retain months of backup data on disk for faster, more reliable
restores and more data recovery points. Quantum's innovative implementation of this core technology
means that users do not have to compromise on performance to take advantage of extended retention
capability. Inline data flow provides streamlined deduplication that offers a maximum combination of total
system performance, manageability, and value.
Quantum's deduplication technology uses a sub-file, variable-length approach to identify redundant blocks
in a data stream—blocks that have appeared before in the same dataset or in datasets processed at an
earlier time. When a block appears that has already been stored, the DXi system inserts a reference pointer
to the earlier instance of the data segment instead of storing another copy. The result is a dramatic reduction
in the storage capacity needed to store the data set, and a similar reduction in the bandwidth needed to
replicate deduplicated data sets over a network.

Compression

The DXi6900 systems use compression technology after duplicate blocks have been identified and replaced
as part of the deduplication process. With compression, unique data that has been through the data
deduplication process can be compressed at a typical ratio of approximately 2:1. This enables you to
maximize the storage capacity of your system.

Space Reclamation

The space reclamation process performs multiple functions on the DXi6900.
When data is deduplicated it is stored in a block pool—a pool of all unique data blocks that were captured
during the data deduplication cycle. When subsequent backup jobs occur, the data deduplication engine
searches for new data entering the DXi and uses a variable length compression algorithm to compare new
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