What are your reasonable options for backing up a 16TB NAS in 2021?
External Hard Drive?
Pros:
- Interface Portability. You do not need any new software or hardware.
- Ability to reuse older hardware: Assuming you have a used drive large enough to hold all your backups.
Cons:
- Interface instability: USB3 drives especially are bad at this. The adapters are usually not designed to handle the multiple hours of uptime necessary to complete backing up multiple terabytes of data.
- Transfer speeds: Most USB3 drives are not designed for performance. Even custom enclosures with reasonable drives in them usually struggle to keep a sustained write speed of 100MB/s.
Tape?
Pros:
- Very reliable: Most tapes will probably outlast the drives that created them.
Cons:
- Expensive: LTO-4 drives are several grand apiece, including used models. LTO-5 or LTO-6 is even more expensive, and LTO-5 or LTO-6 will be needed for most users with a NAS.