Chapter in this post:
Apple's in-house backup solution called "Time Machine" is a recommended macOS feature that you should definitely use. The backups are created in the background - mostly when the Mac is idle anyway - and you usually don't have to worry about anything if everything has been set up correctly beforehand. This includes, above all, the selection of the right storage medium.
What I am writing here are not official recommendations from Apple or rules that someone has set, but are merely tips for you that I have gathered from my years of experience with Macs and with Time Machine. Better suggestions and criticism are always welcome!
No matter which hard drive you get: In order for it to work reliably as a Time Machine Volume, you should open it in the hard drive utility Mac OS Extended (Journaled) reformat. You could too APFS but currently Time Machine does not appear to be 100% compatible with APFS.
I will of course explain in the post below why I consider the following hard drives to be the best choice. If you don't like to read the whole text and just want a few tips, here is a short list of 2,5-inch and 3,5-inch models that you can't go wrong with. My assessment is based partly on my own experience and - if I do not use the model myself - on the evaluation of customer ratings on Amazon.
Bold type denotes my personal choice based on the price and my experience with the brand.
If you can live with the fact that your hard drive comes with its own power supply and is therefore more suitable for iMac, Mac Mini and Power Mac, you will benefit from high capacities and low prices with these hard drives. Almost all models are also available with 6 TB, 10 TB and sometimes also 12 TB. You can make the selection when you are on the product page. At the moment, however, the 8 TB models are the ones with the best price-performance ratio.
Personally, I work a lot on the MacBook Pro and like to have 2,5 inch hard drives that don't necessarily need their own power supply. I have an active 13-port USB hub (described here with a test report), which takes care of all my external HDDs. That saves space on the desk and, if necessary, I can work with the hard drives on the go - without a hub, of course, directly connected to the MacBook Pro.
For the 2,5 inch hard drives, the 4 TB and 5 TB models are the cheapest when you look at the ratio of capacity and price. If you have an internal 1 TB system hard drive in your Mac, you can do very well with a 5 TB Time Machine Volume. For this reason I have listed the 5 TB models here. You can also switch to 4 TB on the product pages if 5 TB is too much for you.
Whenever Apple throws a new macOS version into the ring, I get desperate emails from some Mac users who hastily made the update and ran into problems. Something has stopped working and there is no backup. This is of course very risky, which is why I recommend a 1: 1 backup with SmartBackup, Carbon Copy Cloner or superduper! close.
After all, some users already have a Time Machine backup at the start, but even here there are sometimes problems with the restore and the Mac does not want to import the backup for whatever reason. I've seen too often that people trust Time Machine as the only backup solution and then end up without a backup in an emergency. A popular error message:
An error occurred while restoring from backup. The files could not be restored.
For this reason: Please do not only trust Time Machine, but also make a 1: 1 backup and perhaps an online backup as well Backblaze create - although you can of course not boot with the online backup.
The size of the hard drive plays an important role in Time Machine, as this backup is not a direct copy of the volumes to be backed up, but rather different versions of files are saved over time. As a result, the Time Machine volume must of course be significantly larger than the hard drive to be backed up.
I would recommend that the Time Machine volume be at least four times the size of the hard drive being backed up. For example, I run a 4 TB hard drive to back up my internal SSD on the MacBook Pro, which is one terabyte. The larger the Time Machine volume, the more versions of the documents Time Machine can keep. When it runs out of space, it will have to delete older versions to make room.
This is one of the first questions I will probably ask new users. When I started with Time Machine, SSDs were still so expensive and low-capacity that they weren't really an option for data backup. With falling SSD prices, one could slowly get the idea that one could use an SSD as a Time Machine Volume.
In my opinion, using an SSD as a Time Machine Volume makes little sense for several reasons:
For me, however, the price and the available capacity are the main reasons to rely on rotating hard drives. From my point of view, more capacity is preferable to speed - and USB 3 hard drives on modern Macs are no longer that slow.
The 3,5 inch hard drives usually have the advantage that they are a bit cheaper than the smaller 2,5 inch hard drives. The price difference for a 4 TB hard drive is around 15 euros (80 instead of 95 euros). Furthermore, very large capacities are usually reserved for the 3,5-inch models. While capacities of up to 3,5 or 8 TB are still affordable with the 10 inch hard drives, the 2,5 inch models offer a maximum of 5 TB at a reasonable price (as of 02/2020).
An example of the price difference: The Seagate Expansion Portable (2,5 inches) with 4 TB costs around 95 euros, while the Seagate Expansion Desktop (3,5 inches) with the same capacity only costs 80 euros.
In addition to the price, the size and the power supply also play a role for me. While the 3,5 inch models are always operated with a power supply unit, the 2,5 inch hard drives can usually be supplied with power via the USB port. This makes them much more manageable, does not require an additional socket and is less noticeable on the desk.
The last advantage of the small disks is that you can use them on mobile Macs on the go, as you don't have to rely on a power outlet. For this reason I have only bought the 2,5 inch devices for years.
To break the whole article down to a short statement, I would like to name the hard drive model that I use and with which I have been driving well for years: WD Elements portable (2,5 inch).
I don't have the 5 TB version yet, because a year ago it wasn't available at a reasonable price, but I have already ordered it because it is still available 27% (40 €) discount on the plate gives.
If you work with a modern Mac and have a USB-C port, you might want one USB-C to Micro-B cable order at the same time. With that one can - as described here - Connect "normal" hard drives with a Micro-B connector to USB-C Macs without the hassle of adapters.
If you have any unanswered questions about choosing the right Time Machine medium, please let me know. The comment field is available to you.
Jens has been running the blog since 2012. He appears as Sir Apfelot for his readers and helps them with problems of a technical nature. In his free time he drives electric unicycles, takes photos (preferably with his iPhone, of course), climbs around in the Hessian mountains or hikes with the family. His articles deal with Apple products, news from the world of drones or solutions for current bugs.
The page contains affiliate links / images: Amazon.de