Double Take WhitePapers

Replication for the Masses

IT professionals have increasingly become certain that inorder to ensure company longevity, data must bestored in multiple locations; this is not only ?

Active Directory catalogs information about all the objects on a network, including people, computers, and printers, and distributes that information throughout your network. Security is integrated with Active Directory through logon authentication and access control. Active Directory gives network users access to permitted resources anywhere on the network using a single logon process. It provides network administrators with an intuitive hierarchical view of the network and a single point of administration for all network objects.

To achieve this level of access for services, Active Directory clients use the Service Principal Names (SPN) directory property to locate a target principal name for a service. It is not usually necessary to modify SPNs. They are set up by a computer when it joins a domain and when services are installed on the computer. In some cases, however, this information can become obsolete. For example, if the computer name is changed, the SPNs for installed services would need to be changed to match the new computer name.

When a Double-Take failover occurs, the NetBIOS name of the original source machine will be represented by the target machine. If you are failing over domain servers without Active Directory or member servers, the source?

The rapid growth in storage brought on by the Internet and distributed computing has placed nearly impossible demands on administrators responsible for protecting corporate data assets. The backup window has shrunk to nearly zero and tape backup systems can introduce significant overhead to a production server, seriously impacting its performance. While the importance of backups increases, the impact of periodic full system backups is obvious. Even nightly incremental backups dominate processing while they examine every file system object and then read all files that have changed in their entirety for backup. Performing this process across a network adds additional overhead as the entire process happens across the wire.

Double-Take can enhance the backup process by continuously replicating critical data to centralized servers and using tape backup systems to backup the replica rather than the production servers. Double-Take offloads the burden of periodic tape backups from multiple production servers to a dedicated backup server and makes centralized tape backup a reality, significantly reducing management cost and improving reliability. Regardless of a file?

Citrix MetaFrame offers secure, Internet-based access to Windows, UNIX, and Java-based applications from virtually any device, via any connection. NSI Software's Double-Take provides real-time enterprise data protection and replication. Double-Take can be used to provide high availability and disaster recovery for the profile server that stores Citrix users?

NSI Software's Double-Take provides real-time data protection and replication for cluster environments. This document describes the steps necessary to configure Double-Take to failover from one Microsoft Windows 2000/NT cluster to another.

This document is intended for network administrators with experience installing, configuring, and maintaining network applications, including Double-Take and Microsoft Cluster Service (MSCS).

Read the full Doubletake in Cluster to Cluster Failover Whitepaper

Double-Take is an asynchronous data replication application that utilizes a number of queues as it mirrors and replicates data on the source to the target. Most of the queues are transparent to system administrators and are optimized for the best performance. However, there are a number of settings related to the Double-Take pagefile that can impact the amount of memory Double-Take uses for queuing.

In order to provide maximum Double-Take queuing capacity and system performance, Double-Take servers should be configured with enough RAM to accommodate the maximum Double-Take pagefile (1GB) in addition to the server's other memory needs. When this amount of physical memory is not available, understanding of the following items is necessary to determine the appropriate configuration for the Double-Take pagefile on a server.

Read the Full DoubleTake Memory Usage Whitepaper

Microsoft Exchange Server is a messaging and collaboration server for the most demanding business needs. Its scalability, performance, and enhanced security make Exchange an ideal messaging foundation for enterprise networks. NSI Software's Double-Take provides real-time enterprise data protection and replication. Double-Take can be used to provide high availability for your Exchange server.

This document describes the steps necessary to configure Double-Take version 4.x to provide high availability for Windows 2000/NT servers running Microsoft Exchange Server versions 5.0 or 5.5. These procedures allow a secondary server to assume the identity and role of a failed Exchange server while maintaining the availability of Exchange services with minimal disruption or data loss.

To complete these instructions, you will install Microsoft Exchange Server and Double-Take, and configure Double-Take for replication and failover. Due to the complexities of these applications, this document is intended for network administrators with experience installing, configuring, and maintaining network applications, including Double-Take and Microsoft Exchange Server.

Read the full DoubleTake for Exchange 5.x Whitepaper

Microsoft Exchange Server is a messaging and collaboration server for the most demanding business needs. Its scalability, performance, and enhanced security make Exchange an ideal messaging foundation for enterprise networks. NSI Software's Double-Take provides real-time enterprise data protection and replication. Double-Take also can be used to provide disaster recovery for your Exchange server.

Because of Exchange's server name sensitivity, the limitation of unique names on the network at one time, and Windows 2000 Active Directory, disaster recovery requires a thorough knowledge of Exchange 2000 and Active Directory. To complete these instructions, you will install and configure Microsoft Exchange Server and Double-Take. Due to the complexities of these applications, this document is intended for network administrators with experience installing, configuring, and maintaining network applications, including Double-Take and Microsoft Exchange Server.

Read the Full DoubleTake Disaster Recovery for Exchange 2000 Whitepaper

A firewall is a program that helps prevent unauthorized access to or from a private network. A firewall examines each packet entering or leaving the network and blocks those that do not meet the specified security criteria.

NSI Software's Double-Take, which provides real-time data protection and replication, can be used through a firewall as long as the firewall ports are configured to allow Double-Take servers to communicate with each other.

This document describes the ports used for Double-Take communications, how to verify the port settings for your Double-Take servers, and the proper firewall port configuration for use with Double-Take.

Due to the complexities of this process, this document is intended for network administrators with experience installing, configuring, and maintaining network applications, including Double-Take and firewalls.

DoubleTake for Firewalls, Read the Full Whitepaper

DoubleTake General Application Notes

Internet Information Server (IIS) is a standards-based Web and File Transfer Protocol (FTP) server from Microsoft. IIS is designed to operate on the Windows network operating system and is an Internet standards-compliant HTTP (Hypertext Transfer Protocol) server that also includes FTP and several other valuable Web and FTP related services. IIS permits the user to fully design, create, deploy, and manage Web sites of any size.

This document describes the steps necessary to configure Double-Take version 4.x to provide high availability for Windows servers running IIS. These procedures allow a secondary server to assume the identity and role of a failed IIS server while maintaining the availability of IIS services with minimal disruption or data loss.

To complete these instructions, install IIS and Double-Take, and configure Double-Take for replication and failover. Due to the complexities of these applications, this document is intended for network administrators with experience installing, configuring, and maintaining network applications including Double-Take and IIS.

Read the Full DoubleTake for IIS Whitepaper

Lotus Notes is an integrated e-mail, calendaring, group scheduling, contact and task management, Web browsing, and knowledge management tool. It is an integrated messaging and Web application software platform. Together these products deliver secure, interactive Web applications and a solid infrastructure for messaging and collaboration.

NSI Software's Double-Take provides real-time enterprise data protection and replication. Double-Take can be used to provide high availability for your Lotus Notes servers.

This document describes the steps necessary to configure Double-Take to provide high availability for Windows 2000/NT servers running Lotus Notes server. These procedures allow a secondary server to assume the identity and role of the failed primary Notes server while maintaining the availability of the Notes services with minimal disruption or data loss.

To complete these instructions, you will install Lotus Notes and Double-Take. You will also configure Double-Take for replication and failover. Due to the complexities of these applications, this document is intended for network administrators with experience installing, configuring, and maintaining network applications including Double-Take and Lotus Notes.

Read the Full Whitepaper on DoubleTake High Availability for Lotus Notes

Microsoft SQL Server is a scalable, reliable, flexible, and high-performance relational database management system for Microsoft Windows 2000/NT server-based systems. NSI Software's Double-Take provides real-time enterprise data protection and replication. Double-Take can be used to provide high availability for your SQL server.

This document describes the steps necessary to configure Double-Take to provide high availability for Windows 2000/NT servers running Microsoft SQL Server versions 6.5 or 7.0. These procedures allow a secondary server to assume the identity and role of a failed SQL server while maintaining the availability of SQL services with minimal disruption or data loss.

To complete these instructions, you will install Microsoft SQL Server and Double-Take, and configure Double-Take for replication and failover. Due to the complexities of these applications, this document is intended for network administrators with experience installing, configuring, and maintaining network applications including Double-Take and Microsoft SQL Server.

Read the Full Whitepaper on DoubleTake High Availability for SQL 6.5 and SQL 7

Microsoft SQL Server is a scalable, reliable, flexible, and high-performance relational database management system for Microsoft Windows 2000/NT server-based systems. NSI Software's Double-Take provides real-time enterprise data protection and replication. Double-Take can be used to provide high availability for your SQL server.

This document describes the steps necessary to configure Double-Take to provide high availability for Windows 2000/NT servers running Microsoft SQL Server 2000. These procedures allow a secondary server to assume the identity and role of a failed SQL server while maintaining the availability of SQL services with minimal disruption or data loss.

To complete these instructions, you will install SQL Server 2000 and Double-Take, and configure Double-Take for replication and failover. Due to the complexities of these applications, this document is intended for network administrators with experience installing, configuring, and maintaining network applications including Double-Take and Microsoft SQL Server.

Read the Full Whitepaper on DoubleTake for SQL 2000

NSI Software's Double-Take, which provides real-time data protection and replication, can be used in a Network Address Translation (NAT) environment provided that the framework is established properly. This document describes NAT basics and provides instructions for configuring your Double-Take servers for a NAT environment.

Due to the complexities of this process, this document is intended for network administrators with experience installing, configuring, and maintaining network applications and hardware, including Double-Take and routers. If you are configuring Double-Take for a NAT environment, you must use Double-Take version 4.2.0.2 Hotfix 18503. You must also have a router in place and know how to configure the ports.

Whitepaper on DoubleTake and NAT

It is helpful to understand how Windows systems communicate when implementing a high availability solution using Double-Take's failover capabilities. Double-Take failover can be implemented with very little configuration necessary in small or simple networks, but additional configuration may be required in large or complex environments to ensure that all clients will resolve the source name to the correct IP address.

Understanding how Server Message Block (SMB) communications occur in Windows NT 4.0, Windows 2000, and mixed environments is the key to understanding what actions must be taken at failover in regard to DNS and WINS services. Due to the way SMB is implemented in Windows 2000, pure Windows 2000 environments should require no name resolution adjustments after failover. However, in Windows NT 4.0 or mixed environments, successful SMB communications require specific name resolution requirements to be met.

This document also discusses other networking topics related to failover, including how to view name caches and the ARP cache to troubleshoot. Additionally, common questions such as how failover affects domain controllers and how to fail over IP addresses to remote targets are addressed.

Read the full Whitepaper on High Availability of Windows Networks with DoubleTake

Failover is a component of Double-Take that allows a target to stand in for a failed source machine. The failover target assumes the network identity of the failed source. When the target assumes the identity of the source, user and application requests destined for the source machine or its IP address(es) are routed to the target. Also during failover, the target can assume or add any source shares so that they remain accessible to the end users. A share is any volume, drive, or directory resource that is shared across a network.

Share configuration and failover occurs automatically for Windows shares. Other shares, such as NFS shares, must be configured for failover through the failover scripts.

This document covers the scripting necessary to failover NFS shares. For complete details on configuring failover, see the Double-Take User?

Oracle is a scalable, reliable, flexible, and high-performance relational database management system for many server-based operating systems. NSI Software's Double-Take provides real-time enterprise data protection and replication. Double-Take can be used to provide high availability for Oracle.

This document describes the steps necessary to configure Double-Take 4.x to provide high availability for Windows 2000 or NT servers running Oracle 8i. These procedures allow a secondary server to assume the identity and role of a failed primary Oracle server while maintaining the availability of Oracle services with minimal disruption or data loss.

To complete these instructions, you will install Oracle and Double-Take, and configure Double-Take for replication and failover. Due to the complexities of these applications, this document is intended for network administrators with experience installing, configuring, and maintaining network applications including Double-Take and Oracle.

Read the Full Whitepaper on DoubleTake SQL Replication and failover for Oracle8i

Oracle is a scalable, reliable, flexible, and high-performance relational database management system for many server-based operating systems. NSI Software's Double-Take provides real-time enterprise data protection and replication. Double-Take can be used to provide high availability for Oracle.

This document describes the steps necessary to configure Double-Take 4.x to provide high availability for Windows 2000 servers running Oracle 9i. These procedures allow a secondary server to assume the identity and role of a failed primary Oracle server while maintaining the availability of Oracle services with minimal disruption or data loss.

To complete these instructions, you will install Oracle and Double-Take, and configure Double-Take for replication and failover. Due to the complexities of these applications, this document is intended for network administrators with experience installing, configuring, and maintaining network applications including Double-Take and Oracle.

Read the full Whitepaper on DoubleTake SQL Replication and failover for Oracle9i

This document describes the steps necessary to configure Double-Take for Windows 2000/NT to provide high availability for print servers. Once this configuration is complete, should a disaster happen to the primary server, the secondary server will automatically failover using Double-Take and the printer server will remain available through the network.

To complete these instructions, you will install and configure Double-Take for replication and failover. Due to the complexities of this application and print servers, this document is intended for network administrators with experience installing, configuring, and maintaining network applications including Double-Take.

Read the full Whitepaper on DoubleTake SQL Replication and Failover for PrintServers

Microsoft volume licensing customers Disaster Recovery White paper

VMware GSX Server is virtual machine software for business-critical environments. It is ideal for server and application consolidation. Double-Take provides real-time enterprise data protection and replication.

Double-Take can be used to provide high availability for your VMware server. This document describes the steps necessary to configure Double-Take to provide high availability for Windows servers running VMware GSX Server.

To complete these instructions, you will install VMware GSX Server and Double-Take, and configure Double-Take for real-time replication and failover. Due to the complexities of these applications, this document is intended for network administrators with experience installing, configuring, and maintaining network applications, including Double-Take and VMware.

White Paper about DoubleTake for VM Ware GSX Server