Now the fun begins. You have gathered tons of data and know more about your enterprise than you ever thought was possible. It is time to put all of this knowledge to use. If this is the first time an actual backup and recovery strategy has been implemented, you will be able to tailor the backup domain. If this is an upgrade or application change, you will probably have to work within the confines of the existing layout, making changes as required.

Using NetBackup as the application in this domain, you first want to list all the systems that will be backed up as clients. This will give you an idea of the number of systems that need to be backed up and the distribution of data. Any systems that have a large amount of data, over 100 GB for example, should be noted, as you might want to make them media servers. The other important thing to track with the clients is their network connectivity. If it looks like there are a lot of network-based clients on slow networks, you should consider installing a high-speed backup network. This gives you increased backup and recovery performance, as well as keeping backup and recovery traffic off the production network. It is now common to install a 100Base-T or Gigabit Ethernet network just as a backup and recovery network.

A NetBackup domain requires at least one master server. In most situations, there will be only one; however, we discuss some reasons to have more than one master. The system that you choose for the master will depend on the size of your enterprise-the number of clients, the total number of files being backed up, and the number of storage units you will need. In a smaller environment, the master server can be a system that is already being used for other work or could be a combined master and media server if it is attached to a backup device.

In larger environments, the master server is usually a dedicated NetBackup server, although it could still be a media server. This server must have enough disk capacity to handle the NetBackup catalogs and, potentially, the debug logs. Most of the debug logs are located in /usr/openv/ netbackup/logs. If this directory is not located in a separate partition, you must make sure you do not allow the logs to grow and fill the disk. The largest part of the catalog is the image database, which is located in /usr/ openv/netbackup/db/images. It is not uncommon for this directory to be a separate partition. All of the meta data for all the backups are sent to the master and stored in this image database portion of the catalog.

You must take many factors into account when determining what kind of system to use for the master server. It can be any type of system, any UNIX system or Windows system from the supported systems list. If the master is a dedicated system, you will need enough computing power to support the network adapters plus the NetBackup processes, as well as enough memory to support each. If the system is also a media server, the system resource requirements are higher. With NetBackup, it is not uncommon to share a tape library among multiple media servers. In many of these cases, the robotic control is handled by the master, while media servers share the tape drives, either directly connected or truly shared in a storage area network (SAN).

The total amount of data that must be backed up when full backups are done is a good estimate for the maximum data that would be required to be managed. It is also very important to determine how much data is to be backed up on a daily basis. This is usually an estimation based on the amount of user or application data and the daily rate of change. If a filesystem contains 100 GB of data but only has a rate of change of 2 percent, you only have to worry about 2 GB of data for your daily backups. These two numbers, total data and changed data, are also used to determine how many tape drives are needed and are part of the media requirements formula.

If all the data is located on a couple of large file servers, you should make them media servers by physically connecting them to tape drives and maybe have one more to handle all the network-based clients. If the data is spread throughout your enterprise, you must decide how you want to configure the backup domain. You can configure a dedicated media server or servers and back up all the data over the LAN, or you can distribute media servers closer to the clients. The restriction here will be the SCSI cable length restrictions from the media servers to the libraries.

a significant amount of data resides on clients on a slow network, you should consider either installing a high-speed backup network or, if there is enough data, making one of these clients a media server. The other consideration is the amount of traffic the backup and recovery requirements will add to the existing networks. If possible, you should put the backup and recovery traffic on a dedicated network. If this is not possible, you might have to throttle large backup clients on slow networks or they will dominate the network.

The backup window can also come into play when you are determining media server requirements. Some straightforward formulas are used to calculate how many tape drives are required to back up a known amount of data in a fixed amount of time, assuming no other bottlenecks. If the amount of data to be backed up and the amount of time available result in too many drives required for a single media server, this would indicate another media server is needed. You must always stay within the system constraints when configuring media servers. It does no good to put more tape devices on a server than it has the I/O bandwidth to handle. You do not want to create any unnecessary bottlenecks.