One of my very frequent recommendations is that you purchase an external hard drive for back-up purposes. Backing up to an external drive is probably the most important first step in getting an overall back-up strategy in place.
The question that inevitably comes up then is just which external drive to get.
The problem, of course, is that it’s an answer that keeps changing. Technology evolves, and as a result, so does my recommendation.
Let me give you a few guidelines, and then a few current (as of this writing) examples.
External drive capacity
It’s pretty easy to say you can never have too much capacity: bigger is better.
Of course, more capacity also means spending more money.
The rule of thumb I like to use is this: get an external drive that is at least three times as large as the amount of data you expect to back up.
For example, one of my Windows 8 machines has a roughly 100GB (gigabyte) drive, of which around 65GB are used:
Thus I would recommend a drive with at least three times 65GB, or around 200GB, capacity. That would be enough to hold two complete and compressed full-image backups, along with overhead information such as recovery partitions, and a healthy collection of incremental backups as well.
As I said, that’s a bare minimum, and there are certainly situations where it could end up not being enough, depending on how you configure your backups. If you want extra safety and breathing room, double or even triple my recommendation.
In most cases, the good news here is that your back-up requirements – even after tripling my recommendation – will likely be smaller than the average external hard-drive size currently available.
External drive technology
There are, naturally, several different types of external drives. Connection methods and even power options vary. Some choices are easy; some depend at least a little on your personal setup.
There’s simply no reason not to ensure that your new external drive comes with a USB3 interface, even if your computer doesn’t support it.
If your computer does support USB3, then backups will be faster – potentially much faster – than the previous USB2 standard. If your computer doesn’t support USB3, that’s okay; USB3 is backwards compatible, and will simply operate at the slower USB2 speed.
Some day, when you get a new computer that will, in all likelihood, have a USB3 interface, you’ll have your external drive all ready to take advantage of it.
In my opinion, SSDs, or Solid State Disks (which use high-quality flash memory instead of rotating magnetic platters), aren’t really worth the money for back-up purposes. I say this for two reasons, and probably not the reason you expect:
- Expense: even though they are coming down in price, SSDs are more expensive than traditional hard disks.
- Longevity: the lifespan of magnetic media is pretty well understood. Once written, it stays written for a long time, and even in the worst circumstances, data can typically be recovered from it (albeit at a price, depending on many factors). I’m just not comfortable with SSDs for really long-term storage yet.
And even though I recommend getting USB3 for the speed, there’s no real harm or additional cost involved in getting it. The truth is, when it comes to backups, as long as they complete in a reasonable amount of time, speed isn’t all that important. Thus, the primary feature of SSDs – speed – is unwarranted. In fact, it’s doubly unwarranted, since the speed advantage of an SSD is mostly about reading data, and backups are all about writing to the drive.
What I didn’t mention was ‘wearing out’. Flash memory does wear out the more you write to it, but SSDs have a longer useable lifespan than their cheaper thumb-drive counterparts, and backups actually don’t write as much to the drive as you might think. Yes, they write a copy of everything (or everything that’s changed) each time you back up, but that’s nothing compared to the constant use that SSDs are under – and are designed to handle – as the primary disk drive of a computer.
All that being said, there’s nothing really wrong with using an SSD as a backup drive, as long as it is a true HD-replacement quality drive, and not a cheap thumbdrive. I just wouldn’t recommend spending the money on it.
There are two approaches to powering an external drive.
- No additional connection: the drive is powered entirely by the USB interface.
- An additional external power supply.
The choice is yours, but when making your decision, consider that USB-powered drives are typically small, portable, and slower. Drives with external power supplies are typically physically larger as well as having more capacity, and are able to transfer data more quickly.
I use both, but as it turns out, both of my back-up drives for my main machines are USB-powered. The one with my laptop is an obvious choice: it’s small and portable and easy to travel with. It just turned out that the drive I use for my desktop is also a USB-powered drive – as I said, I’m not worried about speed.
Physical size: if you care, you can narrow your selection based on physical drive size – for example, a 2.5 inch drive versus a 3.5 – but in the long run, that choice will be made for you based on the choices you made above. USB-powered portable drives are generally small, and the drive with external power (and possibly higher capacity) will be physically larger as well.
Rotation speed: I never pay attention to this for external drives, particularly back-up drives. Your interface speed will likely be the limiting factor, so focus instead on getting USB3, if you can. If you’re on USB2, the speed of a faster drive is mostly wasted.
Specifics: what external drive to get
As I said when I started, drives are changing constantly. But with that in mind, here are a couple of drives that I can recommend today – where “today” is January, 2015.1
USB-powered: Seagate 1TB USB3 Portable External Hard Drive. I have three of these: it’s the drive that sits next to my laptop, my desktop, and even my wife’s laptop as well, so you know I trust it. I recently relied on the one I use to backup the laptop when I upgraded the laptop’s internal drive drive, and it worked flawlessly.
All of mine are the 1TB (terabyte – that’s a thousand gigabytes) version, but a 2TB is available as well, and if I were to buy it again, that’s probably what I would get today.
Externally-powered: Seagate 2TB USB3 3.5-Inch Desktop External Hard Drive. Even though I don’t use it for backup, I use one of these as a day-to-day work drive for my desktop machine. The USB3 interface means it’s fast – fast enough for my day-to-day work. Even though that speed might not be required for backing up (which actually applies to the USB-powered drive above, as well), I have no hesitation recommending it as a back-up drive.
Mine happens to be the 2TB version, but checking on it as I write, I see that there are 3TB, 4TB, and even a 5TB version available as well. They’d be hard for me to resist. Like I said, you can’t have too much disk space.
Opinions are easy to come by
Hard disks are a very difficult category of product to recommend. The problem is that the industry is very cyclic: a great hard-drive manufacturer five years ago might be horrible today.
Unfortunately, that’s pretty true for all the major hard-drive manufacturers. Their quality appears to arrive in waves. Fortunately, there’s usually at least one cresting while another is at its low point.
As you can see from my recommendations above, I’ve been pretty happy with my Seagate drives for some time. Naturally, that can change. But it also means that others may feel differently – either based on their own out-of-date experience, or because the market has changed.
So, when you’re shopping for an external hard drive, pay attention not only to the reviews you might read, but to the dates of those reviews.
Just do this
If you don’t have one already, get an external hard drive for backing up. Either of the two I’ve mentioned above, or similar, will do.
And then start backing up.