Helping people with computers... one answer at a time.
I'll look at a couple of ways to back up to a computer located elsewhere, such as on a friend's or family member's computer, and discuss some of the issues of doing this.
I am trying to find a way to backup my computer automatically to a hard drive at another physical location (my parent's house). Is there a way to do this?
This is a pretty interesting scenario, and one that I personally used for some time while my wife had a retail business at a different location from my home. I would regularly backup in both directions - simultaneously achieving "off-site" backups for each.
But there were, and still are, limitations.
Today, there are a couple of approaches to peer-to-peer backup; I'll cover the most appropriate.
There are also a couple of things that people often think should work, and would work in concept, but they simply can't work for practical considerations.
Do not confuse this kind of backing up with peer-to-peer file sharing, which we've heard so much about. This is completely unrelated, except for the concept of "peer".
A peer is simply "someone like you". A co-worker at the same level as you is your peer. A student in the same class is your peer.
We use the same terminology when it comes to computers - two computers connected on a network that have no hierarchical relationship to them - one is not a server, for example - can be considered to be peers: on equal footing and with equal permissions and capabilities.
Peer-to-peer backup simply means that we take two computers and back up files from the first to the second and the second to the first.
While the two computers don't need to be in different locations from each other, we'll say that they are for the purposes of this discussion; by doing it this way, you'll get an off-site backup. Saved in a different location, this backup protects your data from things like your house burning down and destroying all your local machines and local backups.
We first need to rule out image backups, or backups of your entire computer. It's not that the techniques which we're talking about wouldn't work, they would. Perhaps even someday, they'll be practical, but today, they are not.
The problem is the speed of your internet connection and the sheer volume of data that you'd need to transfer to backup your entire system.
According to Akami, the average connection speed in the US is now 3.6 megabits per second.
Now, let's say you had 20 gigabytes used on your system, which is small, by today's standards. (Recall that a byte is 8 bits.)
Math then tells us that it would take over 12 hours to back up your entire machine under ideal circumstances.
Given that circumstances are rarely ideal, that many people have significantly less than a 3.6-megabit connection, and that most have significantly more than 20 gigabytes on their system, you can see that a full system backup would take days.
The result is that peer-to-peer backups are not suitable for full system backups.
On the other hand, they're great for data backups - the backups of only the data files on your machine - which typically don't add up to nearly as much.
I've talked about Dropbox before, but only in the context of sharing files with friends associated or simply across multiple machines.
But the same technology is also a great peer-to-peer backup solution.
When you install Dropbox and create a Dropbox account, it creates a folder which is then shared with all of the machines logged into that same Dropbox account. Update a file on machine A and it's magically updated on machine B whether that machine is across the room or the planet.
Sounds kinda like peer-to-peer backups, right?
You can also use it to share sub-folders with other specific Dropbox users. That way, you can use Dropbox for yourself, but also specify that a particular folder in your Dropbox (perhaps called "remote-backup") should be shared with your friend's Dropbox account. The same thing happens: updates within machine A's remote-backup folder are magically transferred to the remote-backup folder on your friend's machine (or vice versa) without anything more than an internet connection and making sure Dropbox is running on both machines.
The files are also stored on the Dropbox servers, so even if you don't elect to share with a friend, you've got an off-site backup just by using the tool.
Caveat: pick a friend you can trust to use Dropbox with for peer-to-peer sharing. They can see your Dropbox-shared files and you can see theirs. Files are encrypted on the Dropbox server, so no one but the accounts which you authorize can access them.
Dropbox is one example; perhaps the most popular. There are similar, competing services as well. Windows Live Mesh and SugarSync are two examples.
CrashPlan is backup software that, as one of its features, allows you to use a friend's remote computer as your backup storage location.
The beauty of this approach is that it's much more like backup software and can be configured and controlled more like backup software.
The free version allows only peer-to-peer backup with no storage provided by CrashPlan itself. It appears to be ad supported and does not offer "continuous update". Paid versions of the product offer these features and more.
Unlike the Dropbox approach, your data is encrypted before it leaves your machine, meaning that the friend who's been nice enough to allow you to backup to his machine elsewhere cannot see your data.
Disclaimer: I've not used CrashPlan, so this isn't really a recommendation. However, it is the only online backup service which I've found that has the very feature that you're asking for as part of its offering. Make sure to carefully evaluate this, or any product or service that you plan to use for backing up.
If all that you're looking for is an off-site backup, you don't need the data to be stored on a friend's machine, and you can live with the assorted costs and/or limitations of the various services, then any of the general-purpose online backup services may well be worth looking into. Names like Carbonite, Mozy, Jungle Disk and others are examples.
For completeness, I'll throw this out as well.
Particularly because it's what I did.
While my wife had her business, my off-site solution consisted of two approaches:
I used a Hamachi VPN to connect the two machines over the internet, and then simply had batch files or scripts that copied files back and forth as appropriate. This backed up the most critical data nightly.
Each location had an external hard drive on to which more extensive, nightly local backups were placed. Periodically, we would physically swap the two drives as we traveled to and from the business.
The disk swap might not be seamlessly automatic, but it was quite practical.
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