Hacker News Reader

Comment by ama729 | Hacker News Reader

> I've been thinking about ways to create an offline-equivalent backup, so that it can be automated. One way would be to have a computer that is only connected via serial cable, which only accepts new files to be backed up. (No ability to delete via the serial cable.)

A lower tech alternative is to use a Linear Tape-Open drive/cartridge. Not only are they archival safe (20 years+), but either you can use a new one every time or I think there is an option somewhere to only write once.

https://en.wikipedia.org/wiki/Linear_Tape-Open

Edit: Indeed, available since LTO3 https://en.wikipedia.org/wiki/Write_Once_Read_Many

View on HN

If the size of your data is less than 4GB, a box of DVD+R's is also a cheap, secure and convenient way to make read-only backups. Just burn a new disc at the end of each workday, or whatever other interval your schedule and budget allows.

Of course this isn't really automated, but if you have one of those disc changers that people often use with audio CDs, you might be able to turn that into an automated system with a bit of scripting and hardware hacking.

DVD's and pretty much all optical media are terrible for backup. they degrade just siting on the shelf. and one scratch and 'poof' goes your data. I'm surprised as a medium that they have lasted this long. [1]"Manufacturers claim that CD-R and DVD-R discs have a shelf life of 5 to 10 years before recording," note that is "before recording" [1] http://www.clir.org/pubs/reports/pub121/sec4.html

Sure, but shelf life won't be a problem when you burn a new disc every day and you intend to keep at most a couple of months' worth of daily snapshots.

As terrible as optical discs are for long-term archiving, I'm sure their shelf life usually exceeds that of a carton of eggs. That should be enough to protect against ransomware and most other kinds of disasters that can strike a personal computer.

This risk can be mitigated by:

a) Creating multiple DVDs each time you back up (if your dataset is small enough and stable enough that DVDs are an option, doing two burns seems like an acceptable burden to me).

b) Storing parity files[0] on the DVDs to allow you to actually recover from bit rot and disk damage.

[0] http://en.wikipedia.org/wiki/Parchive

Reply on news.ycombinator.com