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In this document, we present the central concepts of Neverfail Heartbeat through both a product a detailed description. This document is primarily useful to those wanting to gain a deeper understanding Neverfail Heartbeat technology, while remaining a valuable reference guide.
Neverfail Heartbeat replicates data updates from one server, termed an Active server, to another server, Passive server. If the Active server fails, the Passive server can take over processing and assume the the Active server, while users perceive only a short break in connectivity to application services. The can be located next to each other to protect against hardware component failures or software crashes the servers can be placed at different locations to offer protection against site failures. For such the Low Bandwidth Module is available to compress the data that is transmitted between the two networking costs are reduced.
Neverfail Application Modules (AMs) run on top of Neverfail Heartbeat to protect specific applications Neverfail modules encapsulate the application-specific knowledge required to obtain Neverfail protection, installation process is greatly simplified. Several standard Neverfail AMs are available to support Exchange, Server, File Servers, IIS and Sharepoint with a variety of anti-virus tools. A development kit is also enable third-parties to develop additional Neverfail AMs.
Neverfail Heartbeat incorporates a number of technologies to provide cluster-class high-availability at a and with simple maintenance:
The installation procedure requires minimal manual configuration and allows the Secondary server to become a near-identical clone of the Primary server, with the same SID, NetBios IP address, System password, etc.
A replication mechanism maintains the relevant data on the Passive server as a near copy, within the constraints of the available interconnection bandwidth, and the requirement not to impede the application processes on the Active server. Thus, on a fail-over, data more up-to-date than replication schemes that only update when a file is closed. Equally, servers which share a NAS or SAN, this technique avoids data-storage being a single of failure.
A proprietary IP filtering mechanism is hooked into the IP stack, permitting near switching of IP address between the Primary and Secondary servers. Mechanisms relying adding or removing IP addresses from Network Cards require considerably longer to switch.
Comprehensive system and application monitoring tools are available which allow candidate servers and network connections to be analyzed pre-install in order to ensure successful installation, and post-install to permit fail-over should application availability be compromised by hardware, network, or application failure.
Introduction
Businesses will continue to increase their dependency upon electronic data processing in their day-to-day. At the same time, hardware, operating systems and many business applications have become commodity Today, most businesses will suffer significant losses if their applications become unavailable. This document introduces Neverfail Heartbeat, a technology that enables the protection of applications against many failures, including application failures, Operating System failures, hardware, network or site failures, at reasonable cost. This protection is based on using interconnected, redundant servers to ensure that user remains connected to a working application irrespective of the nature of the failure.
With redundant servers, the application runs on a single server, but all updates to protected data a Secondary server. If the Primary server becomes unavailable, the Secondary server can take over
In order to ensure successful fail-over from the Primary to the Secondary server, three conditions
An up-to-date copy of all data stored on the Primary server must also be available Secondary server.
There must be logic to detect failures and to re-start the applications that ran on server on the Secondary server.
There must be logic to ensure that the Secondary server is connected to the network, actually start processing requests from clients.
The Neverfail Heartbeat solution addresses the three issues above. Neverfail Heartbeat can be used single site to provide high availability, or across two sites to combine high availability with disaster
Application Modules (AMs) are available to protect Exchange, SQL Server, File Servers, IIS Servers and applications. These applications rarely run in isolation; auxiliary applications are used for virus detection purposes. The delivery of a fully functional Secondary server requires the full protection of all relevant and auxiliary applications. Auxiliary applications can be protected by Neverfail Application Module (AM(X)s). An Application Module Development Kit (ADK) is available to develop AMs or AM(X)s.
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