Backup and Archive Storage: Tape, Drives and Media

Tape generations and what reads what

Most tape in this section is LTO, numbered by generation, and capacity grows with each one: LTO-3 holds 400 GB native, LTO-4 800 GB, LTO-5 1.5 TB and LTO-6 2.5 TB. The larger compressed figure on a label assumes the data shrinks by half or more, which already-compressed video and archive files will not do. A drive reads its own generation and usually only one or two older ones, so an old cartridge may need an old drive. Browse backup disks and cartridges once you know the generation.

Interface, capacity and the media a drive expects

Tape drives connect over SAS, Fibre Channel or, on older models, IDE/ATAPI, so the server needs a matching host adapter. Each drive quotes native and compressed capacity and sustained transfer rate; the drive must be fed data at least at its minimum speed or it stops and repositions constantly, which slows backups and wears the tape. The backup hard drives section lists tape drives and autoloaders alongside disk-based units, while floppy and Zip-era media remain for legacy equipment.

Questions about Backup and Archive Storage: Tape, Drives and Media

Is LTO tape still worth using for backup?

Tape suits large archives that are written once and rarely read: cartridges cost little per terabyte, can be kept offline on a shelf, and are out of reach of ransomware while disconnected. Recovering single files is slower than from disk.

What do the two capacity figures on a cartridge mean?

Native is the raw capacity of the tape. The larger compressed figure assumes the data shrinks by a typical ratio such as 2:1 or 2.5:1, so already-compressed files such as video will fit close to the native number.

Can a new tape drive read my old cartridges?

Only within limits. An LTO drive usually reads its own generation and one or two earlier ones, so old LTO-1 or LTO-2 tapes need an older drive. Compare the generation printed on the cartridge with the drive specification.