What's the best and most secure method of backing up a Mac?

Mac users would be forgiven for forgetting about backup. Hard disk technology means they are bigger, faster, cheaper and more reliable than ever before; and if you haven't had a failure lately, it's easy to become complacent. But there's nothing like a catastrophic failure of your storage to concentrate the mind on backup.

Anybody feeling safe because they are using the latest technology may find their faith may be misplaced. For example, many laptops now use SSDs. Solid State Drives are super fast, and getting cheaper by the day. So they are a popular option in laptops, and the MacBook Air insists you use one. But as much as SSDs act like HDDs, they are not disks, and have their own inherent volatility - so if anything does go wrong with an SSD, it is far more likely to lose all the data than an HDD. Read: SSD versus Hard drive, what is the best storage for your Mac.

This is part of a series of articles that should help you in the event of data loss, including:

Why failed SSDs can be a data-loss nightmare

Despite being incredibly resilient to being dropped or run over, SSDs can still suffer similar problems to the ones you might expect on an HDD. But things that are relatively simple to fix with an HDD simply aren't possible with an SSD.

When files are deleted on an HDD, they aren't really deleted; there is a directory that keeps track of what files live where. Instead of going to the file and setting each block to zero it just tells the directory the file isn’t there. That means the blocks where the file lives can be over written. So long as you haven't overwritten those files, they are retrievable with data recovery software.

SSDs on the other hand, are handled differently. Unlike HDD blocks, SSD cells can't be overwritten, they must be empty before they can store data. So SSDs use a system to manage empty cells, and erase cells that are available to record data. If they didn't use that system, they would quickly become very slow.

With an HDD, so long as the disk is still spinning, and the read head is still controllable, there's still a good chance data recovery software will be able to retrieve some data. With an SSD, if the operating system has lost track of files, either through deletion of through other problems, the data that once lived in those cells will be erased forever.

Read our roundup of the best storage devices available now: Best storage options for Mac

Disk Utilities don't work on SSDs

Disk utilities don't work the same way on SSDs. In fact they don't work at all for SSD data recovery. So if you had, in the back of your mind, a thought that you might be able to retrieve data from a failed SSD, think again - because you can't. Which is a very scary thought.

Aside from the issue of emptying data cells in SSDs, there is also the fact that each cell has a limited lifespan and can only be written and erased so many times before it fails. Most normal use won't reach that number of rewrites for years.

But it's not always that easy to predict. To deal with that, the SSD controllers are basically little computers that run a very complex management system to shield users from this inherent volatility. These drives typically have an additional 10-20 per cent capacity that they use as memory cells gradually fail.

Each bad cell is reallocated a good block from this secret cache of spare cells. But once this cache of spares is used up, that's it. It will cease to work, and sometimes in a spectacularly rude way. Most SSDs will go into a read-only mode, which is fine.

But many, for reasons the manufacturers struggle to explain why, will simply shut down forever and refuse to power up at all.

If you are wondering why I'm so well versed in the potential tragedy of relying on SSDs, it's from personal experience. Eight weeks ago I bought a shiny new Macbook Air, a long overdue upgrade from my trusty Macbook Pro. Four weeks later it developed a problem, so I ran my usual utilities. To my horror nothing could fix the bad node, and the drive was useless until I reformatted it, losing everything on there.

Read next: How to back up an iPhone | How to back up an Apple Watch

The four types of backup you need to be safe: online, local, live & archiving

Thankfully I have a belt-and-braces mentality when it comes to backup. Actually it's belt, braces, and two more belts, as it's a four-pronged approach. So even though one of the backups failed, I still didn't lose any data and had a relatively painless recovery.

It's that response to data loss that I want to share. Because even if you have a backup, these days a single backup is probably not enough to save people from all the pain a catastrophic storage failure can cause.

You can get away with only using one, or maybe two of the backup methods I'm about to outline here. But each has its strengths and weaknesses, so it's for you to decide where you want to skimp if you must.

Online backup is very popular these days, as it offers an inexpensive way to secure your data. The downside of online backup is that the initial backup is slow, and restoring anything more than a few files can take a long time. It's definitely worth doing, but if you need to minimise your downtime you need something quicker.

The fastest way to get back to work after the worst has happened is to have a local backup, one that you can boot from ideally. If you have a local HDD with a complete copy of your boot drive, then restarting with the alt key applied will give the option of starting from the external drive. You could be up and running again in five minutes, which can be a lifesaver if your job depends on it.

There aren't too many downsides to a local backup. They won't help if there is a fire. Only an offsite, or online backup can help there. But otherwise a daily backup to a local drive will be sufficient for most. Although that still leaves the potential for the loss of a day's work.

To make sure you don’t lose anything at all, the third strand of my backup strategy is live backup. DropBox is the leader here, but here are alternatives. Live backup means that as soon as you save your file, a copy is made in your backup. This is amazing, but not practical for whole drives because of the way the software is designed. But if you keep everything you might keep in your Documents Folder, in your DropBox folder, you will secure your most irreplaceable documents.

Read: iCloud vs Dropbox

Protecting from drive failure, losing a drive, or accidentally deleted files

There are two main reasons for backups. Either data is gone due to a failure or loss of a drive, or data is accidentally deleted. Deleted data may mean you want to go back in time, to a point before you deleted it.

This means keeping lots of backups, or partial backups. A full backup may take up a lot of space, so keeping a week's worth of full backups is usually unrealistic.

Instead a full backup is then updated with incremental or versioned backups. So if you know you had a file a week ago, you can go to a backup from that time to retrieve it.

So that’s the three-pronged approach to backup I would recommend.

  • Local backup, for fast recovery
  • Live backup, for your most precious files as you create them
  • Online backup, to secure large amounts of data, but slowly

Additionally, I would recommend the local backup be a bootable drive to minimize downtime. It’s also handy to have at least one of the backups be versioned, or incremental, so that you can retrace your steps to find deleted files.

Local bootable disk backup

Local backups are fastest, but there's the expense of a backup hard drive to consider too. However if you haven't bought an external HDD lately, you’re in for a pleasant surprise. Prices have tumbled over the last few years, and capacities have soared.

It’s now possible to find a good 1TB drive for less than £50, and if you need more, higher capacities are also available and inexpensive. Depending on whether you are backing up a single machine, or a number of laptops and desktop machines, there are a few choices to consider. Read: The best storage for your Mac

If you are backing up multiple desktop machines, you can either choose to buy a drive for each machine, or have one that you back all the machines up to. For the ultimate in fast restoration of your data, individual drives are ideal.

If you can live without the luxury of a bootable backup, then you can get a bigger drive that would be shared by a number of machines. They can be connected by a Thunderbolt or USB 3.0 connection, or some older Macs might be better with a FireWire interface. Check your Mac’s specs to see the available connections.

If you choose to go for a drive that will be shared, you will either need to connect it to one computer and set up sharing. Not a big deal, but it’s best if that machine is left on all the time. For a little extra you can get a drive that attaches to the network. This means it doesn’t require a machine on all the time.

But it is more akin to having cloud storage in your home. Bootable backups aren’t possible, and the backup and restore is a bit slower than a directly connected drive.

Laptop users may still choose network-attached storage, as it means they don’t have to remember to plug the backup drive in. Instead backups can happen over the WiFi network. Another thing to consider is that it will limit the choice of backup software, as networked backup software is typically a little more expensive.

First line of defence: Bootable backups

If you have decided to go with a directly attached drive for individual machines, you'll be able to take advantage of software that creates a bootable backup. Two pieces of software that have amassed a loyal following from Mac fans over the years are Carbon Copy Cloner and SuperDuper!

But there's a new option recently launched called Mac Backup Guru 2.0. It offers similar features to the more familiar backup options, but with a simpler interface and a pretty neat trick up it’s sleeve. So if you’re setting up a backup solution for somebody less computer savvy, it's a good option.

Read: Best bootable backups for Mac including:

  • Carbon Copy Cloner 4.0
  • SuperDuper! 2.7.3
  • Mac Backup Guru 2.1
  • Time Machine

The second line of defence: Live backup

Having a daily backup is a great comfort, especially if it’s a bootable backup. The ability to simply restart a machine the instant the main drive fails is great. But even a once-a-day backup means if disaster strikes, any documents created that day may be lost forever.

Even hourly backups can mean an hour’s work can be lost. But it doesn’t have to be like that. Having a live backup that secures a document as soon as it's saved is now possible. Better than that, it can be even be free.

Since Dropbox launched in 2009, it seems every major international technology company wants in on the game. Currently Microsoft, Amazon, Google and even Apple are offering some kind of free online storage. Which is great, but a little confusing. So here’s how to choose the best fit for your needs.

First of all, how much stuff do you need to secure? If you're already using another backup system, it shouldn't be too much, as it only needs to be documents you are currently working on. If you are never working on more than 15GB of data in a day, and if you are diligent, and careful, live backup can cost you nothing.

For the less disciplined, or people that work on larger amounts of data in a day, a paid service is sensible. The good news is that the paid services are reasonably priced. You just need to figure out how much storage you need.

The best way to answer that question, is to look at the current size of your documents folder, and allow for a little expansion in the future. One of the great things about a live backup, is that it is kept synched with multiple computers. So if you are using multiple computers, perhaps consider the size of the combined documents folder, again with some room for expansion.

If your requirements are between 20GB and 200GB, Apple, Microsoft, Google and Amazon all have good deals, ranging from £6-£36 per year. If you think it’s likely you’ll tip over the 200GB mark, Microsoft appears to have the best deal at the moment, offering 1TB for just £7 per year (at the current exchange rate, as it's charged in dollars at $4.99 per month), but that’s still not necessarily the best option.

If a laptop is one of the devices sharing the live backup folder, it's unlikely there would be room to take advantage of the whole 1TB. So iCloud and Dropbox Pro are both strong contenders at £83.88 and £95.88 respectively. As they both have features that might tempt Apple users.

If over 500GB of storage is required, and I think that's something of a rare requirement for the average user, things can get pretty pricey. With Amazon charging £1,000 per year. So for those users, the budget conscious would choose Microsoft’s bargain offering. Others looking for a more fully featured experience would certainly be best off with Dropbox. Although if you happen to be using Microsoft Office 365, its yearly subscription license for Office, you actually get 1TB included.

To take a look at the individual options of the services offered now, read: Best cloud based, live backup options including:

  • Dropbox
  • Google Drive
  • Microsoft OneDrive
  • Apple iCloud