Mac Mini 256GB SSD users: How is your experience running MacOS from an external drive?

[hajime]

And you are exactly right. Fanless enclosures struggle with sustained activity and it would be silly to run this way a desktop computer from which you expect consistent performance. All external SSSs will throttle their performance as heat nears their maximum, and all SSSs will experience a shorter lifespan from excess heat exposure.

If you absolutely must do this, use the ACASIS TBU401Pro. It’s $25 more and has a fan that you can switch on and leave on when using, and perhaps choose to turn off at idle.

For those of you on any pro M series mini, YES THERE IS a performance penalty from running the system on external volumes. Not noticing it means you only perform lightweight tasks that don’t take minutes to complete in the first place.

There is generally no reason to do this, although I keep bootable media around for testing and development. While I can understand the desire to keep things “simple” by structuring your files all on a single volume, it introduces several unnecessary vulnerabilities to your data, when you could just move your home folder and config App Store to install external (please note it only does this for apps greater than a gigabyte in size, and for best compatibility format your external as MacOS journaled)

The biggest vulnerability is increased risk of corruption which is far simpler to scan a repair on a non-boot system volume.

I’m using an M4 pro mini with a 4TB SSD that’s faster than the ACASIS TBU401 I have it connected to.

There exists ZERO thunderbolt 4 drives that can match the overall speed and performance of your internal SSD. *this will change with thunderbolt 5 enclosures compared against non-pro minis

Is the ACASIS TBU401Pro dead silent? Between it and the OWC 1M2, which is better for the M4 16-256 or 16-512?
Are there lighter and perhaps smaller, reliable external SSD that is faster than the internal SSD of the M4 Mini? An alternative is if I am going to upgrade the machine in 2-3 years, perhaps just get a Thunderbolt 5 enclosure now even I cannot enjoy the high speed with the Mini M4?

 

[Greybeard2017]

Is the ACASIS TBU401Pro dead silent? Between it and the OWC 1M2, which is better for the M4 16-256 or 16-512?
Are there lighter and perhaps smaller reliable external SSD that is faster than the internal SSD of the M4 Mini? An alternative is if I am going to upgrade the machine in 2-3 years, perhaps just get a Thunderbolt 5 enclosure now even I cannot enjoy the high speed with the Mini M4?

I have both the ACASIS and OWC enclosures.

The OWC holds my main data drive which is permanently connected to the mac Mini - it doesn't get more than warm but I don't constantly thrash it.

The ACASIS fan is not dead silent - but its certainly not loud and its not annoying.

My guess would be that TB5 drives will get less expensive over the next few years - they are currently leading edge and there isn't much competition.

 

[turbineseaplane]

There exists ZERO thunderbolt 4 drives that can match the overall speed and performance of your internal SSD. *this will change with thunderbolt 5 enclosures compared against non-pro minis

Not true of the smaller internal SSDs and on the normal, non Pro, Mini

My SN770 2TB in a TB enclosure is faster than the internal Apple SSD (base 256 on normal Mini)

 

[LelandHendrix]

Are you sure that there are ZERO thunderbolt 4 drives that can match the speed of the 256GB internal SSD?

run Blackmagic disk speed test (free in the App Store) to be certain, also run Grekbench to check overall system performance. I should clarify that on some 256GB SSD they run at half potential speed of the 512 because of architecture. However even in these cases, performance as a system drive may be equal.

While throughput of thunderbolt 4 connected drives maxes out at about 2800GB/s, random IO and tiny writes may be surpassed by the internal drive.

On machines with 512GB internal SSDs, there is no competition. With the 256 they may be neck and neck in some regards but it’s never a clear win for performance on Apple Silicon running macOS on external SSDs regardless of internal SSD.

 

[CalMin]

Not sure I understand this. Doesn't right click on the desktop icon > Encrypt work for you. Or you can do it Disk Utility at time of formatting. I have often done this and not noticed any downsides. The encrypted drives mount on boot, same as non-encrypted.

It’s easy to encrypt, but the problem would come when loading up from cold boot.

For external SSDs, the encryption keys are held in the user account not at the OS level. So the user account has to load then the drive will mount.

Because my Home account is on the external SSD, if it is encrypted the OS has no access to the encryption keys in Keychain. I would have to log in before the drive would mount.

A work around is to have another account on the Mac mini, log into that which would mount the external SSD and then fast user switch into the account with the Home folder on the external drive. That’s an extra hoop through i would rather not jump since the machine will never leave my home.

 

[shoarthing2]

. . . . With the 256 they may be neck and neck in some regards but it’s never a clear win for performance on Apple Silicon running macOS on external SSDs regardless of internal SSD.

This thread is titled: "Mac Mini 256GB SSD users: How is your experience running MacOS from an external drive?" . . . are you confident in your assertion: " . . . it’s never a clear win for performance on Apple Silicon running macOS on external SSDs regardless of internal SSD."

A reminder: (from a reddit thread - other mini M4 256GB owners may agree/disagree):

 

[Joe Myers]

Anyone tried this?

GitHub - Kyle-Ye/XcodeLLMEligible

Contribute to Kyle-Ye/XcodeLLMEligible development by creating an account on GitHub.

github.com

 

[ThailandToo]

I wouldn’t do this. Instead, run the OS and small apps off the internal drive which will be plenty. Use the external drive as home folder and to install apps larger than 1GB. Easy settings to do all of this. I was dumb enough to pay Apple’s upgrade pricing, but for a desktop this is the real way to do it. You never know what Apple is going to remove from usability by running this way. If the external drive was really the same as installing locally, AI would work fine. As far as speed goes, I do have an external backup drive that is a TB4 enclosure. It’s so much faster and so much more reliable than USB 3.1, 3.2, 4. If you have this external drive, buy like a Samsung or WD PCIe drive and a TB4 enclosure and you will be able to install a 4TB for less than $400 including everything.

 

[ThailandToo]

This thread is titled: "Mac Mini 256GB SSD users: How is your experience running MacOS from an external drive?" . . . are you confident in your assertion: " . . . it’s never a clear win for performance on Apple Silicon running macOS on external SSDs regardless of internal SSD."

A reminder: (from a reddit thread - other mini M4 256GB owners may agree/disagree):

View attachment 2466542

Those are really slow speeds for a 2024 internal Mac SSD at these insane prices for drive upgrades.

 

[Greybeard2017]

Anyone tried this?

GitHub - Kyle-Ye/XcodeLLMEligible

Contribute to Kyle-Ye/XcodeLLMEligible development by creating an account on GitHub.

github.com

I read the script and decided not to risk it - it was recommended on another thread on this forum

 

[hajime]

I wouldn’t do this. Instead, run the OS and small apps off the internal drive which will be plenty. Use the external drive as home folder and to install apps larger than 1GB. Easy settings to do all of this. I was dumb enough to pay Apple’s upgrade pricing, but for a desktop this is the real way to do it. You never know what Apple is going to remove from usability by running this way. If the external drive was really the same as installing locally, AI would work fine. As far as speed goes, I do have an external backup drive that is a TB4 enclosure. It’s so much faster and so much more reliable than USB 3.1, 3.2, 4. If you have this external drive, buy like a Samsung or WD PCIe drive and a TB4 enclosure and you will be able to install a 4TB for less than $400 including everything.

That is one possible fear. For such "OS in internal and home folder in external" approach, is 256GB sufficient? I think the read/write speed of the 256GB are relatively slow that even some external drives are faster and thus the overall system performance is faster if running the OS off from the external drive.

 

[Mike Boreham]

It’s easy to encrypt, but the problem would come when loading up from cold boot.

For external SSDs, the encryption keys are held in the user account not at the OS level. So the user account has to load then the drive will mount.

Because my Home account is on the external SSD, if it is encrypted the OS has no access to the encryption keys in Keychain. I would have to log in before the drive would mount.

A work around is to have another account on the Mac mini, log into that which would mount the external SSD and then fast user switch into the account with the Home folder on the external drive. That’s an extra hoop through i would rather not jump since the machine will never leave my home.

Thanks for explaining.
I had a 256GB iMac for a few years and often considered putting the User on an external, but every time I researched it, it seemed problematical and I managed by putting large libraries etc on externals. Your problem is not one I remember reading about.

 

[turbineseaplane]

No offense to anyone, but it seems like a lot of FUD regarding booting the OS off an external TB connected NVMe enclosure

Folks have been doing this rather flawlessly, even on ASi, for quite a while now

Many get confused on the reports of "moving the user folder to the external" vs "booting off the external completely, OS and all" ... the latter is far more reliable and simple

 

[ThailandToo]

That is one possible fear. For such "OS in internal and home folder in external" approach, is 256GB sufficient? I think the read/write speed of the 256GB are relatively slow that even some external drives are faster and thus the overall system performance is faster if running the OS off from the external drive.

MacOS and all apps under 1GB aren’t going to take up 256GB of space. I mean not even close. You can set your apps that are over 1GB to install to external drive.

 

[turbineseaplane]

MacOS and all apps under 1GB aren’t going to take up 256GB of space. I mean not even close. You can set your apps that are over 1GB to install to external drive.

That's exactly how you get in a messy pickle of stuff spread all over the place

Much better to boot fully of an external that is large and all will behave normally, as the OS will expect with all things located in a logical location, again, as expected

 

[ThailandToo]

No offense to anyone, but it seems like a lot of FUD regarding booting the OS off an external TB connected NVMe enclosure

Folks have been doing this rather flawlessly, even on ASi, for quite a while now

Many get confused on the reports of "moving the user folder to the external" vs "booting off the external completely, OS and all" ... the latter is far more reliable and simple

I mean it’s been done without issues both ways. The key, again, to use TB not USB devices connected. I have lost data personally from USB connections getting accidentally disconnected. Never had a problem with TB. I hate losing stuff. Surest way to lose is to use USB as it’s just not the same as a good TB enclosure with the assurances of great data transfer.

I wouldn’t want to lost potential features whether one thinks they don’t want AI now but maybe it’s way more later. Tim wants his money.

 

[turbineseaplane]

The key, again, to use TB not USB devices connected

Agree totally -- almost every "bulletproof" experience report I see is with a TB connection specifically, myself included

 

[Allen_Wentz]

Are you sure that there are ZERO thunderbolt 4 drives that can match the speed of the 256GB internal SSD?

Note that at the operational speeds being considered physical distance, port connections, cable competence, etc. all do matter. Internal mass storage provides substantial boot drive benefits unavailable to external solutions.

 

[hajime]

Agree totally -- almost every "bulletproof" experience report I see is with a TB connection specifically, myself included

For those successful “bulletproof” experience, do they keep the Mini on all the time? I think somebody mentioned that their external SSD got disconnected during sleep and had trouble getting it reconnected automatically during wake from sleep.

 

[shoarthing2]

For those successful “bulletproof” experience, do they keep the Mini on all the time? I think somebody mentioned that their external SSD got disconnected during sleep and had trouble getting it reconnected automatically during wake from sleep.

Sleep-states & Wake worked & work properly/seamlessly for me, over the past 15 months, using plural OS instances in (fanless) TB3 & USB4 NVME enclosures. This is (obv) from a mini M2 (base) rather than the M4 (base) specified in the thread title.

 

[DaveFromCampbelltown]

Booting from external drives on Silicon Macs has been a rocky road since Silicon was introduced in 2020. Experience between users has been variable and varied with time. At one time it was so flaky that many people believed that Apple was going to prevent external booting altogether, but the signs are that it has improved recently. Apple now even has an official article about booting from externals, so it is definitely supported.

Having read that article, I did not know about the DFU (Direct Firmware Update) port. It may be that the drives I was having problems with were attached to that port...

 

[Mike Boreham]

Having read that article, I did not know about the DFU (Direct Firmware Update) port. It may be that the drives I was having problems with were attached to that port...

I also didn't know about the DFU port until recently, and never saw it mentioned in all the articles and threads about external booting which I have followed closely since the start of Silicon Macs. I have successfully made many booting externals on silicon macs and can't believe I just got lucky avoiding the DFU port.

 

[turbineseaplane]

The DFU port to avoid here, on the Mac Mini M4, is the middle one on the back, just an FYI for anyone

 

[hajime]

Sleep-states & Wake worked & work properly/seamlessly for me, over the past 15 months, using plural OS instances in (fanless) TB3 & USB4 NVME enclosures. This is (obv) from a mini M2 (base) rather than the M4 (base) specified in the thread title.

The OWC 1M2 is advertised as an USB4, rather than a TB4, drive. To those who have been using it as an external Mac OS boot drive, does it work well? Any problem? Any other better enclosure?

 

[DaveFromCampbelltown]

The DFU port to avoid here, on the Mac Mini M4, is the middle one on the back, just an FYI for anyone

Now, having successfully avoided that port, I can now say that the drive I earlier said didn't work (Seagate Fast SSD), now does work, as an external System drive, with read/write speeds of up to 400 MB/s.