Pro SQL Server 2008 Mirroring

Transcription

1 Pro SQL Server 2008 Mirroring Robert L. Davis, Ken Simmons

2 Pro SQL Server 2008 Mirroring Copyright 2009 by Robert L. Davis, Ken Simmons All rights reserved. No part of this work may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage or retrieval system, without the prior written permission of the copyright owner and the publisher. ISBN-13 (pbk): ISBN-13 (electronic): Printed and bound in the United States of America Trademarked names may appear in this book. Rather than use a trademark symbol with every occurrence of a trademarked name, we use the names only in an editorial fashion and to the benefit of the trademark owner, with no intention of infringement of the trademark. Lead Editor: Jonathan Gennick Technical Reviewer: Glenn Berry Editorial Board: Clay Andres, Steve Anglin, Mark Beckner, Ewan Buckingham, Tony Campbell, Gary Cornell, Jonathan Gennick, Jonathan Hassell, Michelle Lowman, Matthew Moodie, Jeffrey Pepper, Frank Pohlmann, Douglas Pundick, Ben Renow- Clarke, Dominic Shakeshaft, Matt Wade, Tom Welsh Project Manager: Kylie Johnston Copy Editor: Hastings Hart Compositor: Mary Sudul Indexer: Julie Grady Artist: April Milne Distributed to the book trade worldwide by Springer-Verlag New York, Inc., 233 Spring Street, 6th Floor, New York, NY Phone SPRINGER, fax , ordersny@springer-sbm.com, or visit For information on translations, please contact Apress directly at 233 Spring Street, New York, NY info@apress.com, or visit Apress and friends of ED books may be purchased in bulk for academic, corporate, or promotional use. ebook versions and licenses are also available for most titles. For more information, reference our Special Bulk Sales ebook Licensing web page at The information in this book is distributed on an as is basis, without warranty. Although every precaution has been taken in the preparation of this work, neither the author(s) nor Apress shall have any liability to any person or entity with respect to any loss or damage caused or alleged to be caused directly or indirectly by the information contained in this work. The source code for this book is available to readers at

3 Contents at a Glance Contents... iv About the Authors... xii About the Technical Reviewer... xiii Introduction... xiv Chapter 1: High Availability Options... 1 Chapter 2: Database Mirroring Overview...11 Chapter 3: Planning and Best Practices...23 Chapter 4: Database Mirroring Setup...31 Chapter 5: Automating Setup...53 Chapter 6: Maintenance Simplified...95 Chapter 7: Monitoring and Alerting Chapter 8: Upgrading to SQL Server Chapter 9: Reporting Considerations Chapter 10: Planning for Failure Index iii

4 Contents Contents at a Glance... iii Contents... iv About the Authors... xii About the Technical Reviewer... xiii Introduction... xiv Chapter 1: High Availability Options... 1 High Availability vs. Disaster Recovery... 1 Database Mirroring... 2 Failover Clustering... 2 Log Shipping... 4 Replication... 6 Comparing High-Availability Features... 7 Designing a Complete High-Availability Solution... 8 Summary Chapter 2: Database Mirroring Overview Defining Key Terms Choosing an Operating Mode High-Safety Mode High-Performance Mode Understanding Sessions Pausing and Resuming Sessions iv

5 Running Multiple Sessions Understanding Mirroring States Switching Roles Transparent Client Redirection Enhanced Features Log Stream Compression Automatic Page Recovery Availability Enhancements Features by Edition Summary Chapter 3: Planning and Best Practices Step One: Know Your Environment Are Your Servers Ready? Is Your Database Ready? Do You Know Your Service Accounts? Do You Know Your Database Size? Is Your Mirror Comparable to Your Principal? Are You Combining with Other Techniques? Step Two: Know Your Applications How Are Your Applications Connecting to the Servers? Do Any Components Not Support Automatic Failover? Do Your Applications Have Dependencies on Other Databases? Do Your Applications Rely on External Resources? Step Three: Know Your Plan Sample Plan Best Practices Summary v

6 Chapter 4: Database Mirroring Setup Before You Begin Part One: Advanced Preparation Part Two: Pre-setup Configuration Following the Wizard Setting Up Mirroring Manually Step 1: Create Endpoints Step 2: Create Logins Step 3: Grant Connect on Endpoint to Logins Step 4: Set the Principal Partner on Mirror Step 5: Set the Mirror Partner on Principal Step 6: Set the Witness Partner on Principal Step 7: Change the Operating Mode Special Case: Mirroring with Certificates Step 1: Create Database Master Key Step 2: Create a Certificate Step 3: Create an Endpoint Step 4: Back Up the Certificate Step 5: Create Logins Step 6: Create Users Step 7: Assign the Certificate Step 8: Grant Connect on Endpoint to Logins Step 9: Configure Database Mirroring Test, Monitor, and Wrap Up Troubleshooting Common Setup Issues Restore Issues Transaction Log Issues Communication Issues vi

7 Summary Chapter 5: Automating Setup Prepare the Database for Mirroring Back Up the Principal Database Restore Full Backup on the Mirror Database with No Recovery Back Up the Log of the Principal Database Restore the Log on the Mirror Database with No Recovery Create Endpoints on Instances Create Login for the Service Accounts and Grant Connect Set the Mirroring and Witness Partners Change the Operating Mode If Not Using a Witness Helper Procedure to Manage Linked Servers The Master Procedure Parameters Sample Execution The Code Alternative Setup Using PowerShell The PowerShell Setup Script Summary Chapter 6: Maintenance Simplified Routine Maintenance Considerations Transaction Log Backups Backing Up the Log File Write the Script Make the Script Usable Automating Log Backups Managing Log Backup Retention vii

8 Deleting Log Backups Log File Size Identifying Log Files to Shrink Shrinking a Log File Routine Patching and SQL Server Upgrades Installing General Patches Upgrading or Patching SQL Server Fail Back to the Original Principal Reasons to Fail Back to the Original Procedure to Fail Back to the Original Principal Setting Database Owner and TRUSTWORTHY Property Controlled Failover of Mirrored Databases Problems You Might Encounter Procedure to Perform a Controlled Failover Automatic Failover of Mirrored Databases Creating a SQL Alert to Detect Automatic Failovers Using Service Broker to Detect Automatic Failovers Stored Procedure to Respond to a Failover Service Broker Queue Service Broker Service and Route Summary Chapter 7: Monitoring and Alerting Monitoring Components Database Mirroring Status Table Database Mirroring Monitor Job Understanding Warning Thresholds Using the Database Mirroring Monitor Registering Mirrored Databases viii

9 Performing Health Checks Managing Warning Thresholds Using System Stored Procedures Monitoring Managing Warning Thresholds Understanding Performance Counters Configuring Database Mail Creating an Operator Enabling SQL Server Agent Notifications Creating Alerts Warning Thresholds Performance Events Useful Views Using the State Change Trace Event Summary Chapter 8: Upgrading to SQL Server Using the Upgrade Advisor Upgrade Strategies Performing an In-Place Upgrade Considerations Prior to Performing an Upgrade Upgrading High-Performance Mode Upgrading High-Safety Mode Without a Witness Upgrading High-Safety Mode with a Witness Minimizing the Downtime of a Side-by-Side Upgrade Post-Upgrade Procedures Changing Compatibility Level Checking Object Integrity Correct Row and Page Counts ix

10 Setting the Page Verification Method Updating Statistics Summary Chapter 9: Reporting Considerations Using Database Snapshots Creating a Database Snapshot Working with Database Snapshots Dropping a Snapshot Rolling Snapshots Using Log Shipping Implementing Log Shipping with Database Mirroring Configuring Log Shipping for Reporting Using Replication Type of Replication Database to Use Understanding the Terminology Design Considerations Implementing Replication with Database Mirroring Summary Chapter 10: Planning for Failure Detecting Errors Soft Errors Hard Errors Non-Failover Errors Failover Time Failure Scenarios Scenario 1: Principal Server Unavailable Scenario 2: Witness Server Unavailable Scenario 3: Mirror Server Unavailable x

11 Scenario 4: Mirror Server and Witness Server Unavailable Scenario 5: Principal Server and Witness Server Unavailable Procedure to Drop Mirroring Sessions Failover Considerations Procedure to Copy Logins and Roles Planning and Research SQL Server Web Sites White Papers Webcasts Podcasts Free Training Events Microsoft Support Options Summary Index xi

12 About the Authors Ken Simmons is a database administrator and developer specializing in SQL Server and.net. He is a co-author of Pro SQL Server 2008 Administration (Apress, 2009). He has been working in the IT industry since 2000 and currently holds certifications for MCP, MCAD, MCSD, MCDBA, and MCTS for SQL Ken is active in the online community and often participates in the SQL forums on MSDN and SQLServerCentral.com. He enjoys sharing tips by writing articles for SQLServerCentral.com and MSSQLTips.com. When he is not working, Ken enjoys traveling with his wife Susan and son Nathan, and he can often be found on a cruise ship, at a Disney resort, or at the beach in his hometown of Pensacola, Florida. Robert L. Davis is a database administrator and data architect consulting at Microsoft who has worked extensively in setting up and creating automated processes to manage database mirroring for many internal Microsoft applications. He additionally consults with various internal Microsoft IT groups to assist them with their database mirroring needs. Robert is currently working on the Architecture & Performance Engineering team of the CAP application program group. CAP is the internal software used by support personnel for all of Microsoft s customer-facing products such as Xbox, Zune, MSN, Windows Live, and Hotmail. He has over eight years of SQL Server administration experience, much of that in high-availability environments. Rob writes frequently about mirroring and related topics in his blog at xii

13 About the Technical Reviewer Glenn Berry works as a Database Architect at NewsGator Technologies in Denver, CO. He is a SQL Server MVP, and he has a whole collection of Microsoft certifications, including MCITP, MCDBA, MCSE, MCSD, MCAD, and MCTS, which proves that he likes to take tests. He is also an Adjunct Faculty member at University of Denver University College, where he has been teaching since xiii

14 Introduction Pro SQL Server 2008 Mirroring is your complete guide to planning, using, deploying, and maintaining database mirroring as a high-availability option. Mirroring protects you by maintaining one or more duplicate copies of your database for use in the event the primary copy is damaged. It is a key component of any production-level, high-availability solution. This book covers the full spectrum of database mirroring, taking you from the planning phase through the implementation to the maintenance phase and beyond. Who This Book Is For Pro SQL Server 2008 Mirroring is aimed at SQL Server 2008 database administrators and especially at those who desire to mirror their databases in support of high availability. System administrators and operational engineers who manage Windows Server systems that support mirrored database environments will also find much of interest in the book. How This Book Is Structured This book walks you through the basic configuration of database mirroring to the advanced topics you should know after it is implemented. Chapter 1 compares database mirroring with other high-availability techniques and even provides a sample plan that combines multiple high-availability techniques. Chapter 2 provides you an overview of database mirroring, including the different types of implementation and the new features offered in SQL Server Chapter 3 gives you the knowledge you need during the planning phase of database mirroring, providing you with some best-practice techniques you should know before deploying database mirroring. Chapter 4 covers the basic setup of database mirroring using the database mirroring wizard and also provides step-by-step instructions to set up database mirroring using T-SQL. Chapter 5 provides you the scripts you need in order to quickly automate database mirroring setup for several databases at once in order to avoid the time-consuming process of configuring database mirroring on a single database at a time. Chapter 6 provides you the maintenance scripts you need to run on your database mirroring servers in order to keep them running smoothly. Chapter 7 covers the various techniques you need to know in order to monitor database mirroring and to alert you when certain unwanted conditions arise. Chapter 8 walks you through the steps to perform a successful database mirroring upgrade including pre- and post-upgrade considerations. xiv

15 INTRODUCTION Chapter 9 covers the various reporting options you have with database mirroring by taking advantage of database snapshots, log shipping, and replication. Chapter 10 stresses the importance of knowing how your database mirroring configuration will react to different types of failures and what you should do to be prepared for them. Prerequisites Database mirroring was introduced in SQL Server 2005 but wasn t officially supported until Service Pack 1. You can run database mirroring in the original release, but you will need to set a trace flag. In order to run the samples in this book however, we recommend running SQL Server 2005 Service Pack 1 or greater, and if at all possible Service Pack 3. However, in order to take advantage of all of the latest features, you will need to be running SQL Server Downloading the Code You can download the source code for the book on the Apress web site in the Source Code section at All of the T-SQL code will be in.sql files prefaced with the name of the stored procedures used in the book. There will be one PowerShell script with a.ps1 extension. The sample databases are no longer provided as a part of the SQL Server 2008 installation. If you want to download a set of sample databases you can use for testing purposes, they can be found on the CodePlex website at You will want to download the SQL Server 2008 Product Sample Databases from this web site and follow the installation instructions. Contacting the Authors You can contact Ken Simmons by ing him at cyberjunkyks@yahoo.com, or you can visit his blog at There will be a tag on his blog called Pro SQL Server 2008 Mirroring you can use to filter posts that are directly related to the book. Please include the book title in any e- mails to help identify questions or comments about the book. xv