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Introduction to Novell Replication Services

Articles and Tips: article

Product Line Manager
Internet Access Division

01 Aug 1997

Offers a basic description of NRS and discusses the need to replicate files and the value of NRS, including security, scalablility, and ease of use.


Novell Replication Services (NRS) ensures easy, secure, reliable and manageable replication for millions of files, across thousands of network servers, anywhere in the world.

This powerful management tool automatically replicates files and volumes from one server to any number of other servers on your corporate network, intranet or the Internet. NRS eliminates time-consuming, error-prone manual file transfers, batch files or scripts to update and replicate Web files, documents, applications, graphic images, and audio and video clips.

NRS is built to handle the high volume of data required by today's fast-moving, global business environment. It supports one-way and two-way replication, so spreadsheets, presentations and other documents that are created or modified at one location are automatically synchronized across all other applicable locations. The result: you enjoy secure, accurate and consistent data at all locations at all times, without intervention by your network administrators. Best of all, users have immediate read-and-write access to the most up-to-date files and software.

Why Replicate Your Files?

By replicating files, organizations can ensure rapid delivery of information to network users, regardless of the location of the users or the information. By replicating WAN-based information to remote sites, users at those sites can enjoy LAN-speed access to information-even to graphics, audio and video files-eliminating the delays introduced by slower-speed WAN links.

In addition, replication ensures fast and reliable access to critical corporate information despite network disruption due to WAN faults or performance constraints. Organizations can replicate Web sites to improve remote access and server load balancing without jeopardizing content consistency.

What Will NRS Do for You?

NRS delivers significant benefits to your organization, including

  • lower costs

  • improved productivity,

  • higher data availability

  • easy management

Lower Costs

NRS automates the replication process, so you can increase the productivity of the people who are responsible for managing information. A single administrator can manage replication across thousands of servers. NRS includes essential tools that increase administrator productivity while ensuring fast and easy replication:

  • The replication panel allows one-time, easy setup of the data to be replicated and the servers on which replication is implemented.

  • The synchronization panel enables one-time setup of synchronization schedules.

  • The diagnostics panel lets the administrator monitor synchronization and other events.

The WAN-optimized design of NRS reduces WAN traffic. Transaction log synchronization, for example, eliminates the time-consuming comparison of file and directory dates and times across the WAN to determine which files have changed. And link servers ensure that updated files travel only once across the WAN, and over the optimal route. The result is lower utilization of existing equipment, lines and connections, enabling you to postpone purchases of expensive additional capacity.

An innovative scheduling facility enables you to optimize network traffic based on the needs of your organization. You can schedule replica synchronization to occur as often as every minute, or to occur during non-peak hours when users won't be affected by additional network traffic.

Replication puts information closer to users, which reduces WAN traffic, freeing bandwidth for other critical applications.

Data Reliability and Security

NRS takes the worry out of replication by guaranteeing that all replication operations are complete and accurate. Replication operations are transactional to ensure against partial file updates if the network fails. Auto checksumming protects against corruption of the data during transmission over the network. Auto restart after failure feature ensures that replication processes are completed even in the event of a failure. To ensure the most efficient use of bandwidth, NRS continues file replication from the point of the last completed file operation after the system restarts.

NRS works with Novell Directory Services (NDS) to deliver global access control. NDS ensures that only those users who have rights are permitted to access sensitive data, regardless of the user's login location or the location of the data. For example, if a user does not have access to a particular file on a local server, and that file is replicated to another server at another location, that user will still be denied access to that file regardless of where the file resides or where the user logs in. Global access control is handled automatically by NDS without administrator intervention.

Scalability to Millions of Files and Thousands of Servers

NRS is built on a highly scalable replication architecture that is optimized for WANs. Effective synchronization algorithms ensure real-time data consistency across servers with minimum impact on network traffic. NRS detects changes made in any replication directory and automatically replicates only the files that have changed. You can also schedule synchronization to occur at non-peak times and configure it to use the optimal route between any pair of servers.

NRS is designed to support your LAN, WAN, Intranet and Internet . . . no matter how large or how geographically dispersed. Because there's no need to compare file dates and times, NRS can accommodate millions of files. Each master server in NRS can simultaneously replicate data and files to 50 replica servers. Link servers permit chained replication to any level. With as few as three link levels, an NRS master server can support up to 125,000 replica servers.

Ease of Use

NRS uses a simple snap-in to the standard Novell NWAdmin tool and takes advantage of the management infrastructure established by NDS. NetWare administrators are already familiar with the NWAdmin interface, so learning time is minimized.

The NRS setup routine guides you through every step of the installation, so you're up and running in minutes.


NRS is integrated with Novell Web Server, BorderManager and ManageWise. This integration enables you to leverage your investment in these other Novell products.

With NRS, you can replicate content on the Novell Web server plus you can push information to Web servers from thousands of other staging servers throughout the world.

BorderManager enables NRS to replicate data across Virtual Private Networks (VPNs) on the Internet, eliminating the expense and hassles of using dedicated lines for replicating data at remote sites.

Integration with MangeWise enables NRS to locate and notify the administrator when replication problems occur. This helps ensure that data replication is performed according to your policies and specifications.

Find out more about NRS

NRS helps lower the cost of network ownership by lowering the cost of replicating intranet and WAN content. At the same time, it helps you ensure rapid, secure delivery of consistent information to your network users, regardless of their location. The result . . . you maintain the highest levels of data availability throughout your network, while increasing productivity and reducing administration costs. No matter how large your network or how geographically dispersed, NRS gives you easy, secure, reliable and manageable replication for critical information across your entire network.

For more detailed information, including competitive comparisons and answers to frequently asked questions, or to download a trial version of Novell Replication Services, visit the Novell Web site at


Novell Replication Services requires:

  • Novell NetWare 4.1 or greater, or Novell IntranetWare

  • 2MB of server disk space on the SYS volume for every 1,000 replicated files, and adequate disk space on all volumes for the contents of replicated files

  • Between 2MB and 3MB of server memory, depending on server configuration

* Originally published in Novell AppNotes


The origin of this information may be internal or external to Novell. While Novell makes all reasonable efforts to verify this information, Novell does not make explicit or implied claims to its validity.

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