There are several library manufacturers, each with an entire line of libraries from small to very large. Part of this decision will be based on the drive technology you select, as some libraries support only certain drives. The considerations for selecting a library are as follows:

• Does it handle the desired drive type?

• Will it handle the required number of drives?

• Does it support the needed number of slots?

• Does it have expansion capability?

• What type of connection, SCSI or Fiber?

• Does it support barcode labels?

As you look at the different libraries available, you should also consider if your strategy is best served by one large library that contains all the drives and media or by smaller libraries that are distributed throughout your enterprise. We will discuss some of the reasons for picking one or the other later, but part of this decision is whether you plan to implement a SAN or distributed media servers (or both). Generally, it is cheaper to buy one large library than two smaller libraries that equal the same capacity in drives and slots.

A sample of the library vendors are ADIC, ATL, Compaq, Exabyte, Fujitsu, HP, IBM, NEC, Sony, Spectra Logic, and StorageTek. Each of these companies has a Web site that contains all the information for their entire line of libraries. This would be an excellent place to go for information.

Our next step in our discussion of backup and recovery in the enterprise is to take all the data collected and manipulated earlier and actually configure a backup domain. We will use VERITAS Software's NetBackup application for this discussion. In this article, we go through the unique terms and concepts that apply to NetBackup so you can follow the examples more easily. We look at the elements that go into the selection of a master server, to determine if separate media servers are required, and at the actual steps involved in configuring the storage devices for use by NetBackup, as well as configuring a policy to back up clients. We also examine the internal catalog used by NetBackup and configure the automated backup of this catalog. As part of the configuration discussion, we look at the different methods that you can use to perform the configuration.

Each backup application uses its own terminology and NetBackup is no different. We have provided a glossary of the specific terms that are used when configuring NetBackup. To configure a NetBackup domain, you start with the selection of a master server. This server contains all the information about the policies that are configured for NetBackup. A policy contains the list of clients to be backed up, the file list, the attributes controlling the backup and all of the schedules. It also contains the information used to determine where the data will be sent for storage. This configuration information is called storage units and gives NetBackup a logical representation of the physical storage devices. Each media server contains the actual device configuration information. The master server also maintains and manages the database of all the media that is known to the NetBackup domain. This information is kept in the volume database (volDB). In addition to the actual volume information, the master has a database for the volume pool information (poolDB).

Obviously, a good place to start is selecting a system to be the master server. When using an application such as VERITAS Software's NetBackup, your choice is not restricted by the application. You can use just about any UNIX or Windows system that has enough resources. Many people select the type of system that their administrative staff is already familiar with to eliminate the need to learn another operating system. It is very common in an enterprise for the backup master server to be a standalone system. This frees up all the system resources to the backup and recovery requirements of the enterprise and makes the master server independent of other applications. The master server can also be the robotic control host for the tape libraries, especially if it is a dedicated backup server. It is also common to make the master highly available. In some cases, depending on the overall backup workload, the master can also serve as a media server.

Here are several considerations when determining the master server:

• Number of clients to be backed up. The total number of clients to be backed up by a master is important primarily for two reasons. First, this has a direct relationship to the total number of jobs. Second, the number of clients affects the overall size of the catalog and the number of directories within the catalog.

• Total number of backup jobs. The total number of backup jobs scheduled daily and weekly is related to the number of clients and the number of schedules that are run for each client. Database agent backups also affect this number, since it is common for a single database backup to generate multiple jobs.

• Number and type of networks. Network interfaces require system resources-especially high-speed networks like GbE networks.

• Total number of media expected to be tracked. The management of the volDB requires system resources. As the expected size of the volDB grows, the system resources must be available to manage it.

• Will the master be a media server? If the master server will also function as a media server, you must select a system that has adequate I/O capabilities. You must also ensure there is enough memory to accommodate both functions.

There might be more considerations, but this list gives you an idea of what you need to be thinking about when selecting a master server. Remember, this server will be doing all the scheduling for the backups, managing the catalogs for all the backups, keeping track of the status and use of the tape devices, tracking all the active and available media that is known to the system, as well as handling all restores. You should make sure the system you select has enough memory and processor capacity to handle all these functions, as well as enough disk space to hold the catalogs, databases, and logs.

Every backup domain must have a media server. This can be the following:

• Master server as media server. As discussed earlier, a master server can also function as a media server.

• Application server that is also used as a media server. If an application server has enough data to make LAN backups undesirable, it can have tape drives attached, making it a media server. It can either back just itself up or be used to back up other LAN clients.

• Dedicated media server. A system or systems can be dedicated as media servers used just to move data from clients to tape or to read data back in the case of a restore.

• Special SAN media server. The SAN media server is special in that it can only be used to back itself up and cannot be used to back up other LAN clients.

In a larger enterprise, it is common to have dedicated media servers to handle the LAN clients and have the larger application servers also be media servers, used primarily to do LAN-free backups of their data. If there is a SAN, these will probably be SAN media servers. Since the task of a media server is to move the data from a client to tape, it should have good I/O capabilities and adequate memory. The media server can be either a UNIX or Windows system.

As discussed, any system that has data that will be backed up is a NetBackup client. This includes the master server, all the media servers, all the application servers, and any other systems that need to have their data protected. As you make your list of clients to be backed up, you should group them by common attributes. This can either be by function, business unit, architecture, or configuration. When you configure your backup policies, you should group clients with similar backup characteristics.

When you configure any backup and recovery application, you need to configure the specific hardware devices that will be used by the application. With NetBackup, you configure the physical storage devices on the media servers. These devices are first configured with the operating system and then with NetBackup. This allows NetBackup Media Manager to access the devices. NetBackup actually allocates and accesses the physical devices via the storage unit definitions on the master server. This configuration is also required.