This may be useful for someone who like me doesn’t keep up with every geeky development, and so can miss out on things (thanks to Keith Frankish for the heads-up).
OK: you know that it makes sense to back up a lot of your stuff “in the cloud” (we’ll set aside questions of security and sensitive personal stuff — I’m talking about all the rest). At this late date, you don’t need a lecture about backing up from me! And you very likely know about the delights of Dropbox. But maybe you are running out of free space. Or you just want to be doubly secure. What to do (without paying out for a “premium” account)?
Well, you could try the new cloud storage service at copy.com, which is about two months old, and aims to muscle in on Dropbox. Sign up by clicking on this link and you’ll get 20GB of free storage [and — full disclosure — I get 5GB extra storage for every sign-up if you do the email verification to kick things off]. I suspect this is a time-limited early-adopters generous offer to help spread the word. Give it a whirl, as you’ve nothing to lose. Signing up involves no more than choosing a password, downloading an app, and clicking a verification link in an email — nothing scary.
Then what happens? A folder “Copy” is installed, and while the app is running what you put in the folder gets automatically copied to the cloud (you can sync across machines, and can access contents from the cloud from mobile apps — the usual kind of thing you’d expect). Why not give it a go, to increase your cloud storage?
“Ah, but I don’t want to muck about with my folder system and/or I’ve already got a Dropbox folder for stuff I want to backup in the cloud”. No problem. Here’s the promised helpful geekiness: you don’t actually have to move files or folders into the Copy folder — you can just put into that folder a symbolic link to anything you want backed up. E.g. a symlink to your “Current work” folder, or to your iPhoto library, or whatever. (“What’s a symbolic link?” Not an alias — you can Google the difference. The key thing is that a symlink is transparent to Copy and to Dropbox, so putting a symlink into your Copy and/or your Dropbox folder is as good as putting a copy of the file into the folder, except it takes up no space on your hard drive and the copy changes when the file does. Mac users can make symbolic links exceedingly easily using this. )
You can thank me later …
I have a concern about these backup services, which may or may not be irrational. Suppose that I have a folder that is synchronised with one on a server somewhere in the cloud. Now suppose that a file gets changed or deleted in the cloud, perhaps because of a malfunction, or perhaps because someone hacks the server and goes round changing or deleting users’ files as an act of vandalism. Then when I next turn on my own computer, the same changes or deletions might get made on my computer, and the file might be lost for ever (unless I had an additional backup elsewhere).
Does anyone know whether a symbolic link provides protection against this? That is, does the symlink make the updating only one way, so that if I have a file in folder X, a symlink to it from folder Y, and then the cloud server synchronising with folder Y, any changes at the cloud server do not feed back through Y to make changes in X?
Thank you.
Two things protect against that scenario. First, it is very unlikely. More reassuringly, both services maintain redundancy AND a history of your changes. It isn’t immediately obvious from the interface, but you can go back to last week’s version of a file. (Or, of course, your own local backup.) In the eventuality that a hacker first corrupts your file, then destroys the all of Dropbox’s (or copy.com’s) computers and burns down the room in which you keep your local backup, well, then it’s a good thing you kept another backup at your office.
Thanks for the reassurance, David. I was unaware of the scope to go back to previous versions.
Thank you.
Actually, I’ve been using Dropbox for quite a while, both as backup and to sync between devices. (e.g., it allows looking up a student grade on my spreadsheet using my iphone.) The symlink “trick” is one everyone should know; it allows keeping one’s preferred file structure. A nice feature of Dropbox is the ability to exclude some folders in the master Dropbox folder from sync-ing on particular machines (those with limited memory). I’m quite fond of a Finder alternative, PathFinder, which has symlinking built-in.
Through various promotions I’ve gotten Dropbox up to 11GB, though I think some of that will expire. My wife went ahead and bought extra storage that she needed for her book project. Dropbox is very very well implemented; hoping copy is too.