If a disk drive or other failure results in the computer being unusable for a time, it can be a relief to know that you have reliable backups of your data. However, making the necessary repairs and reloading the dumps of the database and logs can take considerable time. A very cost-effective alternative to this is to maintain a "warm" backup server at all times.
SQL Server includes features that make it very easy to have another server standing by in case something should happen to the primary production server. Assume that you have two servers: Primary is the primary production SQL Server and Standby is another server on the network, also running SQL Server, with devices, databases, logins, and user accounts set up identically to those on Primary. Each time a database is dumped from Primary, you will immediately load it onto Standby. Likewise, you will immediately load each transaction log dump from Primary onto Standby. (It is still recommended as a further precaution that these dumps also be copied off to tape or some other medium and stored.) Should a problem arise on Primary that will require significant downtime, Primary can be taken offline and Standby's server name changed to Primary.
If you use this approach, the only downtime will be the few minutes necessary to take Primary offline and to change Standby's name—no user applications will need to change, and the data on the server will be current through the last transaction log dump made from the old Primary server.