Hi, I wonder if, in case someone hacks my linux PC, the backup in Ubuntu 15.10 will be hacked also, e.g. missing. In the worse case, do I have to send backups to a media, disc or stick regularly ?
many thanks,
miramarcos

Why not perform a one time back up of the system and then back up your data regularly. At points where you install new software or change how your system is configured, you can back up either the system again or just the added changes. As far as where you store it, that depends on how much data you have. The system should be small, and data can be very large, but it really depends on what you do have for data.

If you keep the backup outside of the hacked PC, as is normally the case, no.

Yes, and also in the best case. In other words, you need to make regular backups in all cases. Exception: You don't care for the data.

No, but depending on how you do your backups, anything they screw up on the main system might screw up the backup as well the next time the system runs its backup. The way around that is incremental backups using rsync --link-dest for example.

Harden your system, as others suggested do a backup and make it offline as soon as the backup finished. Like a USB or NAS, disconnect or unplug from the system once the backup is done.

What you need to worry about is not someone hacking your system, but hardware failure. HDDs fail, and it's not a rare event. When that happens, your backup is gone. You should always have backups on external media, and if you really care about the data, another copy at another site, because your entire house could burn, and take your external media with it. It all depends on how much you value your backups.

My wife's dad passed away several years ago. Back when computers became popular in the early 90's she had a bunch of old family photos transferred to CD b/c the photos were starting to decay. The photos are irreplaceable. But CDs only last about 5 years.

Hard drives fail. 10 years is a *really* good life for a hard drive. Most don't last that long. I've had drives fail 3 months after the one year warranty was expired.

Before I became a real stickler for backing up, right when we first met, her hard drive crashed and we did not have $1500 to send it off for forensic file recovery. With ~6 weeks educating myself and working very carefully I was able to recover ~98% of her photos.

I have back ups of powers of attorney, last wills and testaments and so on b/c paper can burn. But drives crash and CDs go bad. So, what to do?

I build custom operating systems. When I was learning it took me a year to build the first one. I can do it in ~6 weeks now. Still a lot of work to lose. So I extract the OS in a format that can be installed to other hardware.

I have incremental back ups on a NAS. If that fails I have "every day" USB back up drives in my lab. If that fails I have everything burned to DVD. If that fails (like a fire or theft of *all my equipment*) I have a safe with back up drives in it. If that fails I have back up drives over in storage.

Always CYA 6 ways to Sunday. I'm *probably* not going to get hit every where at once. If my apartment building burns down my storage bin will probably be OK.

Now the stuff in storage is usually 3-6 months out of date. But at least I won't lose my wife's irreplaceable 20-30 year old photos. Or have to cross my fingers and hope that I can forensically extract them from another physically failing hard drive again.

So how much does your data mean to you?