There are two major hardware setups for server backups. The client can back up multiple servers. When finished with the first server, it's easy to detach and move on to the next server. Ease of use. Client backup software is generally simpler, easier to use, and requires no NLMs or other processes to be installed on the server.
Data restoration is more complete.
If the server were to fail, restoration is accomplished by simply getting replacement hardware on the network. With a Netware server, this is done by loading a few DSK drivers and NLMs. With a Unix machine, all that is needed is a bootable kernel disk and a couple of utilities to mount the disks. The client contains the entire server disk. In a small organization of 10-20 people, a business can spend a couple thousand on a nice DAT drive and SCSI cards for all the machines.