Goals of this BookAs I cover how to use the Maintenance Plan Wizard and Maintenance Plan Designer in this book, I have tried to keep the following goals in mind: • to keep the book at a
Trang 1Goals of this Book
As I cover how to use the Maintenance Plan Wizard and Maintenance Plan Designer in this book, I have tried to keep the following goals in mind:
• to keep the book at a level that most non-professional DBAs can understand
• not only to cover the mechanics of how to use the Maintenance Plan Wizard and Maintenance Plan Designer, but also to offer practical advice on how best to maintain your databases
• to provide an easy-to-read, tutorial approach to learning
• to offer lots of best practices from the real world
SQL Server Editions Covered
in this Book
This book covers the use of the Maintenance Plan Wizard and the Maintenance Plan
Designer for SQL Server 2005 and SQL Server 2008, including both the Standard and Enterprise editions If you are running SQL Server 2005, you should be on Service Pack 2
or later, as Service Pack 2 introduced some changes in the Maintenance Plan Wizard and Maintenance Plan Designer which make it closer in functionality to SQL Server 2008 All the screenshots and examples are from SQL Server 2008, which, on occasion, varies from SQL Server 2005 When there are significant differences, I will point them out
SQL Server 2000 and earlier is not covered because Maintenance Plans changed substantially between SQL Server 2000 and SQL Server 2005 Although the implementation changed quite
a bit, the database maintenance recommendations I make in this book still apply to SQL Server 2000 and earlier
Trang 2Maintenance Important?
More times than I can count, I have seen a company install SQL Server databases without first creating any form of maintenance plan These servers hum merrily along with nary
a problem That is, until there is a problem At this point, query performance drops
drastically or servers run out of disk space or, in extreme cases, databases become corrupt And oh, by the way, nobody ever bothered to set up a backup plan, so there are no backups
to restore Oops!
The goal of implementing a database maintenance plan is to help prevent the kinds of problems just described If implemented correctly, a database maintenance plan can
help ensure that a SQL Server's databases perform adequately and, if there should be a problem, provide the necessary backups to minimize the loss of any data Another benefit of implementing a database maintenance plan is that it helps to prevent, or to catch early, many different kinds of database-related problems By being proactive with a good maintenance plan, time spent troubleshooting problems after the fact is often reduced
In this chapter, we'll review some of the most important database maintenance tasks with which a DBA must be concerned, such as database backups and integrity checks, which will
be included in virtually every database maintenance plan
We'll then consider the four major tools available to implement these maintenance
tasks We'll focus on the two tools that are at the heart of this book, namely the database
Maintenance Plan Wizard and the Maintenance Plan Designer, but we will also consider
the options of using T-SQL scripting and PowerShell scripting
The Scope of Database Maintenance
If you were to ask ten different DBAs to define "database maintenance," you would probably get ten different answers The problem is that the term "database maintenance" is not clearly defined within the DBA community Taken literally, the term refers to the maintenance of
SQL Server databases However, most DBAs confer on the term a more general meaning,
encompassing maintenance of not only the databases, but also the SQL Server instances on which they reside, the OS, and the physical box on which SQL Server runs
Every part of the larger SQL Server environment needs to be carefully managed and
Trang 3Chapter 1: Why is Database Maintenance Important?
purposes of this book, I am going to interpret the term quite literally, and define it as follows:
Definition: Database maintenance plan
A database maintenance plan is a set of specific, proactive tasks that need to be
performed regularly on databases to ensure their adequate performance and availability.
In other words, this book focuses solely on databases and on how to use the Maintenance Plan Wizard and the Maintenance Plan Designer to do basic database maintenance
Important as they are, this book does not cover other issues surrounding the health of the broader SQL Server ecosystem As such, while everything in this book is important, it is only
a subset of all the things that a DBA needs to do to maintain healthy SQL Servers For more information on these broader topics, do an Internet search on "SQL Server Best Practices" to find additional information
My goal in this book, indeed the goal of the Maintenance Plan Wizard and Designer, is to cover those critical database maintenance tasks that, as a bare minimum, should be applied
to all databases, to ensure adequate performance and availability Is "adequate" as opposed to
"optimal" performance good enough? This, ultimately, is a business decision, based on the nature of the business function that a given database supports, and on the amount of time, resources, and money that the organization is prepared to invest If an organization doesn't have the resources (or isn't willing to expend them) then, up to a point, it has to accept slower performance and lower availability from its SQL Servers
This is a perfectly rational choice Many SQL Server instances, especially those with small databases or a small number of users, often don't need to be "optimized to perfection" for performance, or even to be highly available If a query takes 15 seconds to return a result, or
if a database goes down for a couple of hours, or even a day, the organization will continue
to function In such cases, the Maintenance Plans covered in this book will suffice to ensure that the databases operate smoothly, and with acceptable performance They will also be well suited to the main target audience of this book; namely accidental DBAs, or full-time DBAs who are just starting out, and who manage smaller non-mission-critical SQL Server installations
The same argument does not hold for databases that support mission-critical business functions In these cases, you will also need to invest time in creating more flexible and powerful maintenance plans, probably using T-SQL or PowerShell scripting, rather than using the Database Maintenance Wizard and Designer Of course, organizations that choose
to have highly performing and highly available SQL Servers have to make a large resource investment to attain this goal There is no right or wrong maintenance plan; just different choices based on different needs
Trang 4Different Approaches to Database
Maintenance
There are many different ways that DBAs can choose to perform database maintenance In this section, we'll take a look at four of these options, including their pros and cons This should allow you to determine which option is best suited to your particular needs
As noted earlier, the focus of this book is on the first two of these tools: the Maintenance Plan Wizard and the Maintenance Plan Designer
Maintenance Plan Wizard
The Maintenance Plan Wizard is one of two tools that SQL Server provides to create
Maintenance Plans
A note on terminology
SQL Server uses the term "Maintenance Plan" (note the capitalization) to refer to a
database maintenance plan created using either the Maintenance Plan Wizard or the Maintenance Plan Designer.
Under the covers, each Maintenance Plan takes the form of an SSIS package, which is then scheduled to run under one or more SQL Server Agent jobs, and will perform the various tasks that make up a database maintenance plan We'll cover this in more detail in Chapter 3 The goal of the Maintenance Plan Wizard is to guide you, step by step, through the creation
of a Maintenance Plan, without the need to do any coding, thus making the whole process easy and quick While the Wizard doesn't include every possible database maintenance feature or option, it does include the core database maintenance tasks that all DBAs should
be performing on their SQL Servers As such, it is often an appropriate tool for the part-time/accidental DBA, or even for full-time DBAs For example, if the databases are small, the number of users is low, high server availability is not required, and there are available maintenance windows, then this tool is more than adequate in most cases
Trang 5Chapter 1: Why is Database Maintenance Important?
It also has the following advantages:
• The resulting Maintenance Plan can be modified and extended, if necessary,
using the Maintenance Plan Designer Many DBAs use the Wizard to create their
"base" Maintenance Plan, and then use the Designer to tweak it
• The tool includes an option to create Multiserver Maintenance Plans, meaning that
you can create Maintenance Plans for multiple servers in a single step However, this feature is awkward to configure and has some backwards compatibility problems, so it may not work for all SQL Server environments As such, I tend to avoid using it The same feature is available in the Maintenance Plan Designer and is discussed briefly in Chapter 16 (though it has the same drawbacks)
In many ways, the Maintenance Plan Wizard does attain its goal of easing the creation of database maintenance plans However, it falls short in some areas, and can cause problems for the incautious The Wizard assumes that you fully understand every option that it offers
to you, and how each affects your databases If you don't understand the options, and you guess at their meaning, it is very easy to create a Maintenance Plan that performs terribly Unfortunately, the Wizard is not smart enough to prevent you making these poor choices However, in this book, I will fully explain all these options so that you can use the tool to its full advantage, and avoid such performance issues
As useful as the tool can be, DBAs must be fully aware of what it can and can't do Having created a few Maintenance Plans with the Wizard, some novice DBAs confidently assume that that their databases are fully maintained As we have already discussed, the Maintenance Plan Wizard only performs core maintenance tasks, rather than every possible database maintenance task that should be considered for a given database or server For example, just because you create backups with the Wizard, this does not ensure that the backups are good (restorable), or that they have been moved off the server to protect them should the SQL Server instance experience a disk failure Such tasks (other examples are covered a little later
in this chapter) have to be done outside of the Maintenance Plan Wizard
The Wizard also has the following specific shortcomings:
• Limited number of database maintenance options If you need database maintenance
options that are not provided, you'll have to resort to T-SQL or PowerShell scripts, or to use scripts for some tasks and the Wizard for others
• Lack of granularity For example, the Maintenance Plan Wizard can't determine which
indexes need to be rebuilt, and which ones don't need to be rebuilt, and therefore has to rebuild them all As such, it often takes more time to execute a Maintenance Plan created with the Wizard than a custom plan created using T-SQL or PowerShell scripts
• Inability to run multiple tasks Each type of maintenance task within a single
Maintenance Plan can only be configured to run once within that Plan This can make