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Oracle® Fail Safe Concepts and Administration Guide
Release 3.3.1 for Windows
Part No. A96684-01
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Introduction to Oracle Fail Safe

Increasingly, businesses expect products and services to be available 24 hours a day, 365 days a year. While no solution can ensure 100% availability, Oracle Fail Safe minimizes the downtime of Oracle databases and other applications running on Microsoft clusters and configured with Microsoft Cluster Server (MSCS).

This chapter discusses the following topics:

Topic Reference
What Is Oracle Fail Safe?   Section 1.1  
Benefits of Oracle Fail Safe   Section 1.2  
A Typical Oracle Fail Safe Configuration   Section 1.3  
Deploying Oracle Fail Safe Solutions   Section 1.4  

1.1 What Is Oracle Fail Safe?

Oracle Fail Safe is an easy-to-use software option that works with Microsoft Cluster Server (MSCS) to provide highly available business solutions on Microsoft clusters. A cluster is a configuration of two or more Windows systems that makes them appear to network users as a single, highly available system. Each system in a cluster is referred to as a cluster node.

Oracle Fail Safe works with MSCS cluster software to provide high availability for applications and single-instance databases running on a cluster. When a cluster node fails, the cluster software moves its workload to the surviving node based on parameters that you configure using Oracle Fail Safe. This operation is called a failover.

With Oracle Fail Safe, you can reduce downtime for single-instance Oracle databases, Oracle Forms and Reports Servers, Oracle Applications, and almost any application that can be configured as a Microsoft Windows service.

Oracle Fail Safe consists of Oracle Services for MSCS and Oracle Fail Safe Manager:

Together, these components enable rapid deployment of highly available database, application, and Internet business solutions.

1.2 Benefits of Oracle Fail Safe

Oracle Fail Safe provides the following key benefits:

1.2.1 Highly Available Resources and Applications

Oracle Fail Safe works with MSCS to configure both hardware and software resources for high availability. Once configured, the multiple nodes in the cluster appear to end users and clients as a single virtual server; end users and client applications connect to a single, fixed network address, called a virtual address, without requiring any knowledge of the underlying cluster. Then, if one node in the cluster becomes unavailable, MSCS moves the workload of the failed node (and client requests) to another node.

For example, the left side of Figure 1-1 shows a two-node cluster configuration where both nodes are available and actively processing transactions. On the surface, this configuration might seem no different from setting up two independent servers, except that the storage subsystem is configured so that the disks are connected physically to both nodes by a shared storage interconnect. Although both nodes are physically connected to the same disks, MSCS ensures that each disk can be owned and accessed by only one node at a time.

The right side of Figure 1-1 shows how, when hardware or software becomes unavailable on one node, its workload automatically moves (fails over) to the surviving node and is restarted, without administrator intervention. During the failover, ownership of the cluster disks is released from the failed server (Node A) and acquired by the surviving server (Node B). If a single-instance Oracle database was running on Node A, Oracle Fail Safe will restart the database instance on Node B. Clients then can access the database through Node B using the same virtual address that they used to access the database when it was hosted by Node A.

Figure 1-1 Failover with Oracle Fail Safe in a Microsoft Cluster

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1.2.2 Easy to Use

Because of the numerous hardware and software components involved, configuring software and all of its dependent components (for example, disks, IP addresses, network) to work in a cluster can be a complex process. In contrast, Oracle Fail Safe is designed to be easy to install, administer, and use and simplifies configuration of software in a cluster.


You can install Oracle Fail Safe either interactively using Oracle Universal Installer, or in silent mode. With the silent mode installation method, you install software by supplying input to Oracle Universal Installer with a response file. Also, you can perform rolling upgrades of both the operating system and application software. Rolling upgrades minimize downtime by allowing one cluster node to continue hosting the cluster workload while the other system is being upgraded. See the Oracle Fail Safe Installation Guide for more information.

Administration and Use:

Oracle Fail Safe Manager provides an easy-to-use interface to set up, configure, and manage applications and databases on the cluster. Oracle Fail Safe Manager provides wizards that automate the configuration process and ensure that the configuration is replicated consistently across cluster nodes.

Oracle Fail Safe Manager includes:

  • A tree view of objects that displays multiple views of the same data to help you find information efficiently

  • Wizards that automate and simplify resource configuration, and drag-and-drop capabilities that help you quickly perform routine system maintenance, such as moving resources across nodes to balance the workload

  • An integrated family of verification tools that automatically diagnose and fix common configuration problems both before and after configuration

  • Online documentation, including a quick tour, a tutorial, help, and manuals available in HTML and PDF formats

  • A command-line interface (FSCMD) for managing the cluster through batch programs or scripts

Figure 1-2 shows an Oracle Fail Safe Manager window. The left pane displays a tree view showing multiple views (and the current state) of clusters and cluster resources. The right pane displays a property page that lists all groups on the cluster that has been selected from the tree view and the current state of those groups. Depending on the object chosen from the tree view, the display in the right pane changes. When you select a particular cluster, node, group, or resource, the property sheet for that cluster, node, group, or resource is displayed.

Figure 1-2 Oracle Fail Safe Manager

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Figure 1-3 shows the Oracle Fail Safe menus and the items within each menu.

Figure 1-3 Oracle Fail Safe Manager Menus and Contents

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1.2.3 Easy to Integrate with Applications

If you want to configure an existing application to access databases or other applications configured with Oracle Fail Safe, few or no changes are required. Because applications always access cluster resources at the same virtual address, applications treat failover as a quick node reboot.

After a failover occurs, database clients or users must reconnect and replay any transactions that were left undone (such as database transactions that were rolled back during instance recovery). Applications developed with OCI (including ODBC clients that use the Oracle ODBC driver) can take advantage of automatic reconnection after failover. See Section 7.10 for more information.

1.3 A Typical Oracle Fail Safe Configuration

Oracle Fail Safe solutions can be deployed on any Windows cluster certified by Microsoft for configuration with MSCS.

Most clusters are configured similarly, differing only in choice of storage interconnect (SCSI or Fibre Channel) and in the way applications are deployed across the cluster nodes.

A typical cluster configuration includes the following hardware and software:

See the Oracle Fail Safe Release Notes for information about the supported releases of these components.

Figure 1-4 shows the hardware and software components in a two-node cluster configured with Oracle Fail Safe. Note that the executable application files are installed on a private disk on each cluster node and the application data and log files reside on a shared cluster disk.

Figure 1-4 Hardware and Software Components Configured with Oracle Fail Safe

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1.4 Deploying Oracle Fail Safe Solutions

Oracle Fail Safe works with MSCS to configure resources running on a cluster, to provide fast failover, and to minimize downtime during planned (system upgrades) and unplanned (hardware or software failure) outages.

Clusters provide high availability because they are designed to manage:

Oracle Fail Safe also allows you to efficiently use resources in the cluster environment by managing the following:

Oracle Fail Safe has a variety of deployment options to satisfy a wide range of failover requirements. Chapter 3 explains how to configure an Oracle Fail Safe solution for your business needs, including active/passive solutions, active/active solutions, partitioned workload solutions, and multitiered solutions.

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