A good backup strategy is the best defense against data loss. The following are three common backup strategies with questions to consider when determining what is appropriate for your computer system.Network backup or server only    Do you plan to back up your entire network, or do you have storage devices attached to certain servers where users copy their important files?Individual or local computer backup    Does each computer need a storage device? Is each user responsible for backing up his or her data?Server and computer backup    Does each department have a storage device and a designated user to back up all data for that department?You can physically connect your storage device to a local computer or to a server. Table 12.1 lists some advantages and disadvantages of each configuration.Table 12.1 Comparison of Server-Only and Local Computer Backups

Backup Type	Advantages	Disadvantages
Server-only	Fewer storage devices are needed.  There is less media to manage because shared media stores multiple backups.  If each server has more than one client computer, server-only backup costs less than backing up individual computers.	Registries and event logs of remote computers are not backed up.  Backups and restorations are slower, due to network throughput.  Backups and restorations require greater planning and preparation. They must be scheduled when network traffic is low or when critical information can be backed up as quickly as possible.
Local computer	Fewer network resources are committed to lengthy backup procedures.  File recovery is quicker.	Using more storage devices costs more.

Backups that include computers running both Microsoft® Windows® 2000 Server and Microsoft® Windows® 2000 Professional combine the advantages and disadvantages of server-only and local computer backups. Additional considerations include the following:

• If you run backups from a server, you can back up and restore that server quickly. However, if your network has more than one server, the speed advantage is lost.
• Servers typically operate 24 hours a day, so it is possible to run backups during less busy hours. However, if a problem with backup hardware occurs, you might have to turn off the server.
• As a rule, if data is primarily on one server, it is better to run backups from that server.

NoteWhether you run remote backups from a local computer or a server, it makes sense to place the storage device on the portion of your network with the greatest bandwidth or highest transmission frequency. You might also consider keeping the storage device in a secure room.Figure 12.1 illustrates local computer and server-only backup options for a tape drive.Figure 12.1 Server-Only and Local Computer Backup ConfigurationsCautionBackups protect data against viruses. Because some viruses take weeks to appear, it is recommended that you keep normal backup tapes for at least a month to make sure that you can restore a system to its uninfected status.
source: https://technet.microsoft.com/en-us/library/cc938511.aspx