Brad’s Sure Guide to SQL Server Maintenance Plans- P31 docx

Chapter 12: Back Up Database (Full) Task 151 For the typical database, using one of the above strategies will allow you to perform full backups nightly. If your database is so large that neither of these two options will work, then you probably shouldn't be using the Maintenance Plan Wizard to perform your backups. Backing up large databases (100 GB or more), often requires more sophisticated backup strategies, which are best handled using third-party tools, T-SQL or PowerShell scripts. If your databases are large, and if scripting and third-party tools are not an option, then you may need to consider running full backups less frequently, and performing differential backups (covered in the next chapter) on the days in between. Configuring the Back Up Database (Full) Task The Define Back Up Database (Full) Task screen, shown in Figure 12.1, is more complex than most of the Maintenance Plan Wizard screens we have seen up to this point. The first thing I want to point out is that the Backup type drop-down, at the very top of the screen, contains the value Full, and is grayed out. That's because we are on the Back Up Database (Full) task, and the Wizard is smart enough to complete the option for us. Database and Backup Component Selection The next option is the Database(s) drop-down box that we've seen many times before, and which you use to select the databases that you want to subject to full backups. In previous chapters, we've often seen Object and Selection options presented here, allowing us to narrow the scope of a given task to defined objects within the database. In essence, the Backup component options, below the Database(s) box (both of which are currently grayed out) offer a comparable service for backups. When these options are not grayed out (more on this shortly) you can either select Database to back up the whole database, which you will almost always want to do, or you can select Files and filegroups to back up only specific files or filegroups within that database. Chapter 12: Back Up Database (Full) Task 152 Figure 12.1: This is the most complex screen of the Maintenance Plan Wizard we have seen so far. Chapter 12: Back Up Database (Full) Task 153 Let's take a look at this in a little more detail. In order to be consistent with the previous tasks, we would normally want select All user databases. However, in order to demonstrate the next feature of this task, let's instead select a single database, AdventureWorks, as shown in Figure 12.2, and click on OK. Figure 12.2: The two options under "Backup component" will only be available if you select a single database. Now, under Backup component, you'll see that Database is available and selected, but Files and filegroups is grayed out, as shown in Figure 12.3. This means that the whole database will be backed up. If we had not selected a single database, then both Database and Files and filegroups would still be grayed out. This is because these two options only work if a single database has been selected. Figure 12.3: You have two choices, either to perform a full backup or, if a database has multiple files or file groups, to back up only a portion of the database. Chapter 12: Back Up Database (Full) Task 154 The Files and filegroups option only becomes available if a single database is selected and is composed of multiple files or filegroups, which AdventureWorks is not. However, if it were, you'd be able to select that option, and so choose to only perform a full backup of specific files or filegroups, selected using the browse button. This option is sometimes useful for large databases but I would say that, if your databases have multiple files or filegroups, then you should probably not be being using the Maintenance Plan Wizard for this task. Sure, it will do it for you, but if you are at that level of database complexity, you should really be using T-SQL or PowerShell scripts to perform this task. Now, let's get back to the practical use of the Maintenance Plan Wizard. Go back and choose our usual option of All user databases, as shown in Figure 12.4. At this point, both of the Backup component options are grayed out, so we'll automatically be performing full backups of the whole of each of the user databases. Figure 12.4: When you choose two or more databases to back up, the two "Backup component" options will not be available. The next available option on the screen is Backup set will expire. It is not selected by default, and the two options below it are grayed out, as shown in Figure 12.5. Figure 12.5: Assuming you create backups sets, you can choose when they expire. Chapter 12: Back Up Database (Full) Task 155 This option determines when a backup set can be overwritten, and it is designed for people who back up their databases directly to tape. Virtually nobody backs up a SQL Server database directly to tape any more, so you will not need to select this option. The next option is Back up to, where you can choose between backing up to disk, or to a directly attached tape drive, as shown in Figure 12.6. Figure 12.6: You will always choose Disk. As discussed, the only real option is to back up to disk, so leave this option set to Disk. Don't back up directly to tape SQL Server supports the option to directly back up a database to a direct attached tape drive (the tape drive is physically attached to the SQL Server), but this option is virtually never used. Why? Backing up to a tape drive directly from a single server is expensive ( you need a tape drive for every server), dicult to administer, unreliable, and slow. Today, virtually all databases are backed up to disk first, then either stored on a SAN, NAS, in centralized tape library or, in some cases, Internet backup services. Backup File Storage In some ways, the next section of the screen, shown in Figure 12.7, forms the heart of the backup task, since it allows us to define how and where the backup files are stored. Let's look at each option in turn. Backup databases across one or more files If you choose this option, you can either back up to a backup device, which is a pre-created file that can hold one or more backups, or create striped backups, which allow you to perform a backup of a database on two or more physical files at the same time. Backup devices are a holdover from previous versions of SQL Server and are no longer used much by DBAs. They are hard to work with and don't offer many advantages over standard backup files, which we will discuss in the next section. . to Disk. Don't back up directly to tape SQL Server supports the option to directly back up a database to a direct attached tape drive (the tape drive is physically attached to the SQL Server) ,. databases directly to tape. Virtually nobody backs up a SQL Server database directly to tape any more, so you will not need to select this option. The next option is Back up to, where you can. used. Why? Backing up to a tape drive directly from a single server is expensive ( you need a tape drive for every server) , dicult to administer, unreliable, and slow. Today, virtually all