Essential System Administration, 3rd Edition

Network Backup Systems

So far, we’ve considered only backups and restores of disks on a local computer system. However, many organizations need to take a more unified and comprehensive approach to their total backup needs. We will consider various available solutions for this problem in this section.

Remote Backups and Restores

The simplest way to move beyond the single-system backup view is to consider remote backup and restores. It is very common to want to perform a backup over the network. The reasons are varied: your system may not have a tape drive at all since not all systems come with one by default any more, there may be a better (faster, higher capacity) tape drive on another system, and so on.

Most versions of dump and restore can perform network-based operations (Tru64 requires you to use the separate rdump and rrestore commands). This is accomplished by specifying a device name of the form host:local_device as an argument to the -f option. The hostname may also optionally be preceded by a username and at-sign; for example, -f chavez@hamlet:/dev/rmt1 performs the operation on device /dev/rmt1 on host hamlet as user chavez.

This capability uses the same network services as the rsh and rcp commands. Remote backup facilities depend on the daemon /usr/sbin/rmt (which is often linked to /etc/rmt).^[19] To be allowed access on the remote system, there needs to be a .rhosts in its root directory, containing at least the name of the (local) host from which the data will come. ...