Microsoft SQL Server 2008 R2 Unleashed- P75 pot

Policy-Based Management Best Practices Policy-Based Management is one of the new management features introduced in SQL Server 2008.. Policy-Based Management enables an organization to de

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CHAPTER 21 SQL Server Clustering

What has happened is that the application can no longer connect to the failed SQL Server

(because you turned off CLUSTER1), and it is still in the middle of failing over to CLUSTER2

in the two-node cluster

A failover occurs in a short amount of time; the actual amount of time varies, depending

on the power and speed of the servers implemented and the number of in-flight

transac-tions that need to be rolled back or forward at the time of the failure (A complete SQL

failover often occurs in about 15 to 45 seconds This is very minor and well within most

service-level agreements and high-availability goals.) You then simply click the Retrieve

button again in the Connection Test Program, and you are talking to SQL Server again,

but now to CLUSTER2

As you can see in Figure 21.27, the data connection has returned the customer data,

SHOWDATETIME has been updated, and SERVERNAME still shows the same virtual SQL Server

name that the application needs to connect to, but the SPID has changed from 55 to 52

This is due to the new connection of the Connection Test Program to the newly owned

(failed-over) SQL Server machine The Connection Test Program has simply connected to

the newly started SQL Server instance on CLUSTER2 The unhandled exception (error) goes

away, and the end user never knows a complete failover occurred; the user simply keeps

processing as usual

NOTE

You could program better error handling that would not show the “unhandled

excep-tion” error You might want to display a simple error message, such as “database

momentarily unavailable—please try again,” which would be much more user friendly

Potential Problems to Watch Out for with SQL Server Clustering

Many potential problems can arise during setup and configuration of SQL Server

Clustering Following are some items you should watch out for:

SQL Server service accounts and passwords should be kept the same on all nodes, or

a node will not be able to restart a SQL Server service You can use administrator or

FIGURE 21.27 Executing the Connection Test Program again against the failed-over cluster

node

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Summary

a designated account (for example, Cluster or ClusterAdmin) that has administrator

rights within the domain and on each server

Drive letters for the cluster disks must be the same on all nodes (servers) Otherwise,

you might not be able to access a clustered disk

You might have to create an alternative method to connect to SQL Server if the

network name is offline and you cannot connect using TCP/IP You can use named

pipes, specified as \\.\pipe\$$\SQLA\sql\query

It is likely that you will run into trouble getting MSCS to install due to hardware

incompatibility Be sure to check Microsoft’s Hardware Compatibility List before you

venture into this installation

Summary

Building out your company’s infrastructure with clustering technology at the heart is a

huge step toward achieving five-nines reliability If you do this, every application, system

component, or database you deploy on this architecture has that added element of

resilience And, in many cases, the application or system component changes needed to

take advantage of these clustering technologies are completely transparent Utilizing a

combination of NLB and MSCS allows you not only to fail over applications but to scale

for increasing network capacity

The two-node, active/passive node is one of the most common SQL Server Clustering

config-urations used As you become more familiar with SQL Server Clustering and your

high-avail-ability requirements get closer to five-nines), you might need to put in place other, more

advanced configurations, such as four-node SQL Server clusters and/or datacenter-class

clus-ters (of up to eight-node SQL Server clusclus-ters and active/active variations) If you follow the

basic guidelines of disk configurations and database allocations across these disk

configura-tions, as described in this chapter, you can guarantee a certain level of stability, performance,

and scalability SQL Server Clustering is one of the best, most cost-effective solutions, and it is

literally “out of the box” with SQL Server and the Windows family of servers

Remember that SQL Server 2008 supports other concepts related to high availability, such as

data replication, log shipping (soon to be deprecated), and database mirroring You might

use these solutions rather than SQL Server Clustering, depending on your requirements

Clustering is a very complex subject The information contained in this chapter is

suffi-cient to start you in this area, but for a much more complete and thorough understanding

of how to assess your high-availability needs, to evaluate what you should build for high

availability, and to implement a high-availability platform that uses MSCS and SQL Server

Clustering, you should find a copy of Microsoft SQL Server High Availability by Paul Bertucci

(Sams Publishing) This book is loaded with full explanations, a formal approach to

achieving five-nines reliability, and numerous live examples

Chapter 22, “Administering Policy-Based Management,” explains how to affectively

administer servers using the Declarative Management Framework

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CHAPTER 22

Administering

Policy-Based Management

IN THIS CHAPTER

Introduction to Policy-Based Management

Policy-Based Management Concepts

Implementing Policy-Based Management

Sample Templates and Real-World Examples

Policy-Based Management Best Practices

Policy-Based Management is one of the new management

features introduced in SQL Server 2008 Policy-Based

Management enables an organization to define policies to

manage one or more SQL Server instances, databases, or

objects within the enterprise In addition, policies can be

evaluated against target systems to ensure that the standard

configuration settings are not out of compliance

Policy-Based Management was developed in response to the

following industry trends:

Increasing amounts of data being stored

Data center consolidation and virtualization

Growing product capabilities

Proliferation of SQL Server systems within the

enterprise

Need for a way to manage SQL Server settings from a

holistic perspective

Regulatory compliance demanding secure and

stan-dardized settings

Introduction to Policy-Based

Management

A data explosion has been occurring over the past several

years In a 2006 study, International Data Corporation (IDC;

http://www.idc.com) reported that 5 exabytes of digital

media (5 billion gigabytes) were stored in 2003, and in 2006

this had ballooned to 161 exabytes Not only is more data

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CHAPTER 22 Administering Policy-Based Management

being stored, but users are accessing more data than before Part of this data growth is a

result of the need for business intelligence (BI) systems to deliver actionable insights

becoming more critical in the enterprise Obtaining these insights requires large data

volumes for trending and forecasting As a result, data warehouses are becoming more

crit-ical in every enterprise

This data explosion frequently results in a proliferation of SQL Servers

Essentially, DBAs are being required to do more, frequently with less In addition, the

increasing complexities of the SQL Server product set are forcing DBAs to focus on

effi-cient, scalable management and standardization Due to the large numbers of SQL Servers

involved, management by automation becomes critical as well to lessen the administrative

burden Monitoring also becomes more important to provide proactive support

A well-managed SQL Server enterprise that follows best practices offers the following

advantages:

Standardization—Every SQL Server will have a common disk layout and settings,

as well as consistent naming standards As a result, DBAs moving from one SQL

Server to another will not be surprised by different disk layouts or unusual settings

that could account for a performance problem

Best practices—Microsoft internal studies have shown that 80% of the support calls

to their Customer Service and Support (CSS) could have been avoided if the

customer had been following best practices Best practices not only offer

perfor-mance advantages but also lead to fewer failure events caused by poorly configured

SQL Servers, and security breaches due to SQL Servers that have not been hardened

(security holes not locked down)

Ease of deployment—A well-managed data center will have automated procedures

for building SQL Servers (that is, unattended installations using configuration files)

that require less time to build and minimal administrative interaction, resulting in

fewer mistakes in a build and a reduction in administrative tasks

Regulatory compliance—By maintaining controlled and standardized settings,

organizations can easily adhere to the demanding requirements of regulations such

as Sarbanes-Oxley, the Health Insurance Portability and Accountability Act (HIPAA),

and Payment Card Industry (PCI) standards

The intent of Policy-Based Management is to provide a management framework that

allows DBAs to automate management in their enterprise according to their own set of

predefined standards By implementing Policy-Based Management within a SQL Server

infrastructure, organizations can reap the following benefits: total cost of ownership

asso-ciated with managing SQL Server systems will be reduced, configuration changes to the

SQL Server system can be monitored, unwanted system configuration changes can be

prevented, and policies will ensure compliance

The stated goals of Policy-Based Management fall into three categories:

Management by intent—Allows DBAs to enforce standards and best practices from

the start rather than in response to a performance problem or failure event

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Intelligent monitoring—Allows DBAs to detect changes that have been made to

their SQL Server environments that deviate from the desired configuration

Virtualized management—Provides a scalable framework that allows for

manage-ment across the enterprise

Microsoft SQL Server 2008 and SQL Server 2008 R2 also ship with several predefined

poli-cies These policies are not automatically imported into a default installation of SQL Server

2008 However, you can manually import them into SQL Server and use them as is or as a

foundation for defining your own similar policies These sample policies can be found in

C:\Program Files\Microsoft SQL Server\100\Tools\Policies\DatabaseEngine\1033

Note that there are also policies for Reporting Services and Analysis Services, which can be

found in the ReportingServices and AnalysisServices subdirectories of the Policies

directory Also note that Policy-Based Management can be used to manage SQL 2005 and

2000 servers

NOTE

Microsoft has a blog focusing on Policy-Based Management (http://blogs.msdn.com/

sqlpbm/) where it publishes scripts that can be used to enforce Microsoft best

prac-tices for SQL Server, as well as tips, tricks, and tutorials for using Policy-Based

Management

Before we start learning about enforcing Policy-Based Management, there are a few key

concepts DBAs must understand These concepts include

Facets

Conditions

Policies

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