Desktop Macs should get backed up via Time Machine (TM) to an external drive permanently connected to it.

As a rule of thumb, the TM drive capacity should be at least twice the internal storage of the backed-up computer.

So, if your iMac has a 1TB internal drive, the TM drive should have at least 2TB of storage.

The reason is that the backup size will continuously grow, even if you delete files (in fact, that's partly the point of having a backup).

If you plan/need to store additional data on an external drive, I strongly recommend buying another one rather than occupying space on the TM drive.

For MacBooks, using an external hard drive is feasible (and recommended) but not super practical.

MacBook models equipped with an SD card slot could use something like the Transcend JetDrive (whose capacity goes up to 1TB) as a TM drive:

On the plus side, TM backups are guaranteed to run automatically
On the minus side, it's more expensive than an external hard drive of the same capacity and the read/write speed will be lower

Another solution for MacBooks (especially those without a built-in SD card slot) is to invest in a Network Attached Storage (NAS) solution, like those from Synology.

A NAS is basically a big hard drive connected to your router via an Ethernet cable, thus accessible by all devices connected to your Wi-Fi network.

It's then possible to allocate a portion of the NAS storage for TM, allowing automatic backups of your Macs (both desktop & laptops).

In fact, iMacs used professionally should definitely get backed up in a redundant fashion, both to an external drive directly connected to it and to a NAS.

In both cases, I strongly recommend encrypting the TM backup so that no one except you can access it, should the drive or NAS be stolen.

You might be wondering: "And what about cloud backups?"

Indeed, the best backup strategy is also referred to as "the 3-2-1 backup strategy"

3 copies of your files
2 different mediums
1 offsite

In the past, a different medium would mean having a backup copy of the data on tapes or DVDs.

Nowadays, as long as the backup is on a different drive than the internal one, it's good enough IMO.

The offsite copy is important because it will protect your data in case of fire, flood or robbery.

In practice, it could mean, either a copy in the cloud or on another hard drive stored in a different location (safe at the bank or a friend's house).

The former is the easiest to implement but can prove more challenging when the time will come to actually restore terabytes of data while the latter requires rotating TM drives on a consistent basis (the more frequent, the better).

Please don't consider files stored in iCloud Drive, OneDrive, Dropbox (or similar) as a backup copy, because those services mainly offer data synchronisation and limited file recovery.

If one of your devices gets compromised and a hacker deletes all your data, this will propagate to all your other devices very quickly.

A true cloud backup should be a unidirectional process and the cloud copy should be fully encrypted so that even the cloud provider can't access your data.

My cloud backup provider of choice is Backblaze for the following reasons:

it offers the ability to use our own encryption key
it's very affordable ($70 per year per computer for unlimited storage)
it will backup data from both internal and external drives (except TM backups)
it has a companion app for iPhone and iPad (to easily access files on the go if needed)

You can get a 1-month free trial if you use my Backblaze affiliate link: https://secure.backblaze.com/r/012jt5

Please note that I'll also get 1 month free when you use that special link 🙂

And you, how do you back up your Mac(s)?

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