What site do you recommend for online backup, that doesn't cost any money and can back up entire folders?

I have a Dropbox account, but the free level doesn't offer enough storage--only 2 GB. The only other application I know is Google Drive, but iI use Firefox, and Google Drive is demanding I download Chrome in order to enable uploading entire folders.

Buy a USB Drive?

You get what you pay for. Want unlimited/huge space, then pay for it, period. That goes for Dropbox, Google Drive, Box, OneDrive, or whatever other cloud-storage scenario you can think of.

Personally, I have no problems using rclone to sync from Linux to Google Drive, and 15GB is enough for what I use it for, and I get that free.

What TB0ne says mainly.Our company is small and we do pay Citrix for online storage, one of the things you get when you pay for it is support for restoring lost data. Either case, you want free, then use google docs or dropbox, but don't cry about limitations on space. This is about business not free services just because they're grandiose.

rsync is the fundamental technology that you can use. Here is a good, well-rounded introduction to the topic.

Rsync-based backup tools worth considering is another discussion of good tools, based on rsync, that are likely to be useful.

Pragmatically, what you need is a daemon that, running under privileges that allow it to reach the files in question, sync's those files into a directory that ordinary users ... at best ... can only read, so that L33T H4X0RZ can't touch them. Furthermore, it needs to be an incremental backup so that you can easily recover past versions of any file.

Apple's now-ubiquitous Time Machine utility ... provided with every Macintosh ... is a definitive and thoroughly well-done implementation of this idea, and, at its core, it is basically built upon rsync. Whether-or-not you have (or, need) such a "cool front-end," you do need a daemon that is ... at least, every hour or so ... combing through the "resources to be protected" and making a copy of them into a place that cannot be reached by mortals.

I think this type of response (which I see frequently) is rude in principle, because it disregards that I was interested specifically in online backup; also because the commenter didn't suppose I already own USB drives. Perhaps I was interested in online backup regardless of whether I use USB drives. To answer any post with merely 'use something else' is dismissive out of hand.

rsync and a USB is "secure" and is "online" and there's even "application" front-ends for rsync.
It works on every version of every OS I've tried it on.
USB sizes are economical too.
How much more "online" you need?

You're Welcome.

And the original question, "I want free services.", "... Oh, there are some, but I don't like them, so tell me about more." is similarly not rude in principle? You've posted on LQ for quite some time, I can tell you have expertise with Linux and computers. You've obviously used some of the free online backup services, where did you get the impression that someone is offering free unlimited online backup "just because"?I'll not fully defend Habitual, it was a terse reply, however what if they feel that backing up online is inadvisable? I certainly have questioned whether or not it makes sense. As I've said, we do pay for it; however what happens if blah-blah company goes belly up? What happens if blah-blah company gets attacked by hackers and all data is exposed, or in question. I've brought this up as we've evaluated solutions.

My best advice is whatever hosted solution you go with, encrypt before write.

rtmistler put it best; your question was (essentially): "I want something totally free to do exactly what I want, so instead of doing any research of my own, I want you to tell me".

Habitual's answer was on the money...don't like the free online backup solutions? Use something else. If having the same thing said to you in 100 words vs. 4 makes it different somehow, there's no real solution for that. I've posted a tutorial on this very site about how to get rclone working with Google drive specifically for online backups, which is easily found with a brief search. Putting "free online disk space" into Google pulls up plenty of lists, telling you capacity you get for free...and you didn't bother telling us how MUCH data you want to back up, so how are we even going to suggest something for you to use??

Again; want more space? Pay for it. Dropbox supports Linux well, Google Drive works fine via rclone for backups, Box can be 'mounted' as another disk, and even Microsoft Onedrive works under Linux. ALL of this information could easily be found with some very basic research, such as putting "google drive sync in linux", or "onedrive in linux" into the search engine of your choice.

"Dropbox" is simply an overglorified "rsync."

True, but I do have to commend it for its cross-platform integration, ease of use/setup, and the addition of a web front-end.

I think this is especially true when one wants to hand over his/her personal (sensitive?) data to some random, remote and potentially unreliable "free" service, just because it's free of charge and because doing "online backups" sounds cool. Of course I'm not speaking for those who actually need a remote storage service, in which case the word "free", as others suggested, should be removed from the list of requirements altogether, and the service itself should at least be proved thrustworthy. Perhaps my way of thinking is not "modern" enough, but well, that's the way it is.

Agree totally. I encrypt everything before uploading it, no matter where it goes.

About a month ago I saw a post here that had a link to some linux program that was supposed to let you access almost any online storage. Wish I could remember it. Might try to search. Seemed like a good program. Think one could even automate it.