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Protecting the ever expanding data that collectively is the information that businesses rely on for growth has come to the forefront of the IT industry. Rarely does a company reduce their net storage capacity or the amount of data they retain, even in the face of stiff budgetary constraints. And though more cost effective technologies have been developed, completely and effectively protecting what is inevitably many copies of the same data is a major challenge for many businesses.
Standard practices and conventional technologies are being pushed to their limits in many backup environments, most to an unsuccessful or inefficient outcome. This challenge is common for many Symantec NetBackup (NBU) customers, and finding the right new technology to bridge the gap between current state and desired state is often a long and difficult process.
Data Domain provides an alternative nearline storage solution for NBU customers who are faced with never-ending data growth and unabated storage expansion associated with ballooning amounts of backup and archive data. While NBU is one of the most scalable data protection solutions available to the market, data growth and data retention requirements drive near-continual expansion of NBU storage resources. The scope of this whitepaper focuses on how the Data Domain deduplication storage solution integrates with standard NBU architectural and operational environments in order to overcome the growing gap between what is actually being accomplished and what needs to be accomplished.
NBU Architecture and Terminology
NetBackup (NBU) is a client–server software solution designed for enterprise customers. The core product functionality includes backup/recovery, archive/retrieval, and disaster recovery. NBU allows for a flexible solution. The following figure illustrates a typical NBU architecture.
Each NBU master server records and manages a backup image Catalog. An environment can be configured with a number of media servers, or one server acting as both a master and media server, managing shared or individual pools of storage units. These storage units include a variety of platforms that allow for both onsite and offsite data copies to be made. More commonly, these platforms are tape libraries copying from one onsite tape to another sent offsite. Common terminology used in this whitepaper is provided in the following table.
Typical NBU Challenges
The typical NBU environment supports anywhere from a handful to thousands of clients. NBU scales by adding additional storage unit resources, and associated media server resources to manage them. The most common challenges in NBU environments include:
- Leveraging available storage unit resources for maximum utilization and throughput.
- Contending with extremely large client backups
- Eliminating redundant data backups (copies of databases, aggressive backup retention policies, etc.)
- Eliminating performance bottlenecks (NBU servers, networking, client, tape drives, etc.)
- Managing and storing large amounts of tape media
- Lack of reporting disciplines.
- Keeping up with catalog growth.
Technology Overview
Data Domain reduces unnecessary NBU data storage via inline data deduplication and traditional compression. Data deduplication is performed on incoming data streams and allows only the new segments of data to be identified and stored as unique instances within the Data Domain file system. The following table lists key terminology for Data Domain.
Data Domain data deduplication methods are more granular and variable than fixed segment size data deduplication competitors. Data Domain segment length is variable ranging from 4-16KB. This is a significant differentiator from competitive products which perform deduplication at the file level or at a block level.
Since the rate of primary data change (newly introduced unique 4K to 16K segments) at most sites stays about the same from night to night at most sites, the amount of physically consumed storage for subsequent full NBU backups is roughly the same as the physically consumed storage for a differential incremental NBU backup. The ratio of protected storage size to incrementally consumed physical storage each night stays about the same, but the periodic compression factor of an incremental backup is much lower than the periodic compression factor of a full backup (because the former is much smaller in size). As a result, it is very inexpensive to include many versions of files on a Data Domain system. The relative size of protected data and incremental backup data, before and after de-duplication and compression is illustrated in the following figure.
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