Book Image

Microsoft SQL Server 2008 High Availability

By : Hemantgiri S. Goswami
Book Image

Microsoft SQL Server 2008 High Availability

By: Hemantgiri S. Goswami

Overview of this book

<p>Every business has it's mission critical applications and data. Therefore, it is very important to keep database servers up and running all the time – 24 X 7. There is a need to store and process terabytes of data to cater for business needs, and it is vital to make data highly available.<br /><br />High availability is all about the site being accessible all the time. High availability solutions minimize the downtime for these mission critical applications.</p> <p>Microsoft SQL Server is a powerful relational database engine, widely used to store and maintain data in Enterprises of various levels be they small, medium or large.</p> <p>This book will teach you how best to use these readily-available options and save you time in making your websites highly available.<br /><br />This Microsoft SQL Server 2008 High Availability book will take you through pre and post installation concepts and common issues you come across while working with SQL Server HA. It will teach you how these various HA solutions can be installed using GUI and the command line. It will also show you how to troubleshoot common issues you may encounter whilst installing or managing the HA option in your environment. It provides references to external links for more advanced learning on the topic.<br /><br />This book starts with an introductory chapter into the windows domain, domain users and various handshake methods available with Windows server. It also offers information the different authentication methods available with SQL Server - giving you an insight into the importance of security. After you are through with the security aspects, your journey to installing SQL Server HA will start. It will cover the concepts of database mirroring, log shipping, clustering, and replication.<br /><br />By the end of this book you will be confident enough to take up the challenge to install any of the SQL Server HA options.</p>
Table of Contents (18 chapters)
Microsoft SQL Server 2008 High Availability
About the Author
About the Reviewers

How clustering works

A highly available application or system is the key concept in cluster environment. Microsoft SQL Server is a cluster-aware application, and it works well to cater for this business need. Let's see how it works.

Before we go further into details, let's see some common terms here:

  • Active/Passive Cluster: In this setup, there will be one server that remains idle and takes over the control or the ownership of the resources at the time of failover.

  • Active/Active Cluster: Here, the only difference is that both the nodes in the cluster are active and running, and the surviving node will take over the control or the ownership of the resources when a failover occurs.

  • Public Network: This is a network available to external resources or systems.

  • Private Network aka Heartbeat: This is a network that is available to SQL Server cluster nodes only; heartbeat is used to check the health of another node.

  • Shared Disk Array: A disk array is nothing but more than one disk used collectively and shared among the cluster nodes. However, at any point of time only one node — the active node or the owner of the resources — can access the disks, in order to protect data from being overwritten.

  • Quorum: This is the disk resource wherein the status of the cluster is being written, especially by the Windows clustering. Failure of this resource can lead to failure of the entire clustering setup.

  • Cluster Name: This is the name of a Windows cluster.

  • Cluster IP: This refers to the IP address on the public network that is used by external systems or client machines to connect to the cluster.

  • Cluster Resource Type: This can be any resource that can be configured for clustering, that is, a physical disk.

  • Cluster Account: This is the Administrator account used to control and run the services for a cluster; this account must be configured at the domain level and should be added to the local administrator group in each cluster node.

  • Cluster Group: This is a kind of container, for example, SQL Server, wherein cluster-aware applications or services are grouped.

  • Cluster Name for Virtual SQL Server: This is the name of a Virtual SQL Server, which is then used by client machines to connect to.

  • IP for Virtual SQL Server: This will be the IP address used by SQL Server, and clients use this IP address to connect to SQL Server.

  • Full-text Search: SQL Server Full-Text search.