The decision to go with tape or disk is depended on the backup process that will be decided to implement.
TAPE
-Tape cartridges are easy to ship from production location to an offsite facility for long-term storage, this is a simple DR protection policy.
-Maximum throughput of an LTO drive is 280 MB per second (reading and writing to a single LTO tape drive is faster than a single drive)
-Tape drive are susceptible to bits of dust and tape drive also start and stop a lot. All this causes wear and tear in a typical tape-based backup.
-Tape drive can take several minutes to load, mount and position before a single byte can be read from them.
-If a file has not been accessed over couple of years, it does not really need to be on the main production server, it can be stored on less expensive media at another location.
Tape also still has a place for off-site disaster recovery protection where disk-based replication is not an available option.
Newer LTO tapes use WORM (write once, read many) security that prevents accidental overwriting from ever occurring.
Tape is still a good option if cost is an issue. Tape is still cost effective per GB.
DISK
-Finding a particular file with a disk system is faster.
-Disk has high level of security because the data is not travelling anywhere.
-Users are no longer relying on tape as the primary storage medium
-Backups can be faster depending on the type of network
-Restores are almost always faster
-Network backups provide superior disaster recovery protection
