A practical guide to backing up Mac and external drives

#backup #Mac #bestPractice

Backup Mac computers

Time Machine

Time Machine is a no brainer. Hook up an external hard drive to your Mac, format it to APFS*, open Time Machine, click back up. It will automatically back up all of your data on the computer (Machintosh HD Data) every hour and remove old backups when needed. Most importantly, it works flawlessly with icloud storage. Although there are some pitfalls, Time Machine remains to be the best choice for average users.

To recover your data, simply navigate to the folder/parent folder you want to restore and open time machine. I will discuss advanced methods for data recovery in later sections.

As of 2023, HDD is still the best option for Time Machine backups. Make sure you get one that’s 2x-4x the storage of your Mac (or total size of files to be backed up). Bombich suggests not to use HDD with Shingled Magnetic Recording (for APFS) but I have yet encounterd any issue. Bombich also suggested some models to use but they are quite expensive. I recommend Seagate Backup Plus Hub** for a more economic option.

*Apple implemented the all-new Time Machine with APFS. For pros and cons, check this post: Time Machine Evolution and APFS

**All links to Amazon are affiliated.

iCloud

Technically, iCloud is a storage solution but not a backup solution. Nevertheless, your data is “safe” on iCloud (not subjected to hardware damage). You may also restore an earlier version of a document using iCloud.

Other options

Carbon Copy Cloner is loved by many. It allows you to create bootable backups. For more details, pros and cons, refer to their website.

Backup External drives

Time Machine

External drives connected to your Mac can be backed up using Time Machine. Make sure you have a lage-enough Time Machine drive (again, follow the 2x-4x rule). Simply remove the drives from “Exclude from backup” list under Time Machine settings. Now your external drive is being backed up.

However, things can get really messy.

Apple implemented the new Time Machine structure in recent years. Therefore, many troubleshooting / solutions online do not work with the newest MacOS. Here’s an example to demonstrate furstrations that you may have when restore your external drive from Time Machine backups. Feel free to skip this part if you just want to learn about the solutions.

John, a 5th year PhD, has a 2TB SSD that he uses to store all of his experiment data. One day, he connected it to his MacBook and found that it couldn’t be recognized.

“Damne it!” He thought, “thank God I have it backed up!”.

He then erased the SSD and it seemed to work again. So he tried to restore the data from his Time Machine backups. However, for some reason, he could not enter Time Machine using Finder.

Now he started sweating.

After 30 minutes of Googling, he found the problem: Mac does not recognize the erased SSD as the old one; and a solution: a simple command line that associates the erased SSD to the backups will do the magic.

Nope, that didn’t work.

Desperate John finally found the hidden option in the Time Machine menu: Browse Other Backup Disks, which allowed him to restore files to the re-formatted SSD.

However, this generated a new problem: How to continue backup using the same hard drive? Because the SSD is now recognized as a new one, so Time Machine refused to continue the backup. Instead, it generated a new Volume which require new storage space. Unfortunately, the HDD John uses as the Time Machine is not big enough to backup another 2TB of data. He ended up having to either delete old backups (backups can only be deleted by date but not by folder, which means his laptop backups will all be gone) or to buy a new HDD and back up everything from scratch.

The obvious issue of using Time Machine to back up an external drive is that the drive is recognized as part of your Mac storage. You cannot make old backups compatible with new drives but only to start a new backup. Moreover, the new Time Machine structure does not allow deleting a single folder/Volume from the backups. Therefore, there’s no way to free up space by getting rid of backups of un-wanted data.

Here’s how you can properly restore data on external drives from Time Machine:

1. click Time Machine icon, hold option, click browse other backup disks
2. navigate to your Time Machine drive, select a backup, find the backup and Volume/files you want to restore
3. right click, select restore to…
4. assign a destination

However, this method, still, does not allow you to continue the backup with a new (or reformated) drive. So you’ll inevitably face the same issue.

Carbon Copy Cloner

Carbon Copy Cloner (CCC) is one of the best solutions when it comes to backing up a Mac. It really shines when you want to make a copy of your data where it compares source and destination and have tons of options that you can customize. However, that all come with a price. CCC6 charges ~$40 for a liscence that can be used on multiple computers. You can also go with the edu discount to save 10 bucks.

CCC is extremely intuitive to use. For the best performance, get two identical SSDs, one for use and the other for backup. For a more economic way, you can create a volumn on an external HDD (the one you use for Time Machine backup works) and backup files routinly. Bombich have a list of recommended drives that I found really helpful.

For version control, CCC takes advantage of APFS snapshots, which allows you to store edit history locally. However, make sure to disable/delete CCC snapshots before/after transferring large amount of data or it chews up the space of your drive quickly.

A good use of CCC is for backing up the Time Machine drive, which gives you two copies of bootable versions of your Mac.

SSD Cloner

Cloning your SSD is another way to backup your data. This can be done by using Disk Utility or SSD Cloners. The downside is that you have to do it manually and every time you clone the drive, it has to transfer everything on the SSD to another which can take a while. Some SSD cloners allow offline cloning, e.g. Sabrent SSD Cloner works quite well. However, you’ll have to buy SSD and enclosures and manually install it everytime to clone. Alternatively, you can just use the Sabrent Cloner as your everyday SSD but it requires a giant external power adapter to work.

RAID

When it comes to backup, RAID can never be overlooked. If you decide to dig into RAID, make sure you know how to recover your data if one drive fails.

Conclusion and choice of external storage

As you can see, there is no win-win for data backup. Time Machine offers okay performance, excellent usability, but very poor capability when it comes to external drives. CCC is extremely powerful but it comes with a price. Generally speaking, if you use backup-in-the-background solutions (Time Machine, CCC, etc.), a large storage HDD is your best choice for backup drives. There are debates on using APFS format on HDD but that’s what Apple recommends for Time Machine. If you decide to go with manual backups, get yourself some SSDs.

In terms of choice of external storage: HDDs are cheap, somewhat reliable, but slow; SSDs are fast and small in size but pricy and with limited storage space. At the time of writing, only a few companies offer 4TB SSD and some are quite finicky (i.e. Sandisk Extreme Portable v2 4TB requires a USB2 cable to format). The most reliable SSDs are still Samsung T7 and Sandisk Extreme Portable v2 (< 2TB versions).

If you really want to assemble your own external SSD, make sure you buy the correct enclosure (M/B key) and be aware of head dispensation, especially for NVMe.

If you really want SSD with larger storage, there are only limited options at the time of writing: dual bay NVMe that supports JBOD and is BUS powered simply don’t exist

1. best shot is to get a commercial 4TB SSD
2. some companies makes >4TB ones, but you’ll have to find a proper enclosure for it
3. dual bay NVMe enclosure with two USB ports that is 2x BUS powered does exist. Make sure you improve its heat dissipation if both SSDs will be running at the same time
4. dual bay NVMe enclosure with external power adapter
5. 2.5“ SATA SSD with enclosures

2.5“ SATA SSD are often overlooked. They are bigger and slower but cheaper and still much faster than HDDs, and consume less energy. There are enclosures that can house 2 of them in JBOD/RAID and require no external power (BUS powered), which gives you 8TB storage with 500 MB/s read/write speed at a reasonable price.

My backup strategy

I have two Macs that are synced using iCloud. I put all of my files on iCloud Drive (including some application database that is not recommended to be stored on cloud). When I only had 2TB of external data, I used two 8TB Time Machine, one connected to each Mac, to backup both the Mac and my external SSD when it’s connected.

Now I have 4TB of external data and have experienced what John went through. I have two Sandisk Extreme Portable 4TB (which is not the best option). I use one for storage and the other for backup via CCC weekly. Each Mac is still hooked to their own HDD Time Machine for hourly backup. I swapped one 8TB for a 20TB HDD to also backup the external SSD via Time Machine.