Has anyone tried setting up a Fusion Drive on the ARM-based Macs? I did this many years ago on my Intel Mac Pro, and considering doing it on my M2 based Mac Mini.
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Fusion Drive on ARM Based Macs
- Thread starter melvinlusk
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The fusion drive used to be a useful method to get more storage space (and a bit more performance) at a cost-saving.
But, now that SSDs have come down in price, it no longer makes economic sense to add a spinning hard drive to the SSD that you would already have. Note that Apple no longer offers spinning hard drives (or fusion drives) in any system.
Technology moves on.
A fusion drive would be a step down from the SSD that you already have in your ARM based Mac.
But, now that SSDs have come down in price, it no longer makes economic sense to add a spinning hard drive to the SSD that you would already have. Note that Apple no longer offers spinning hard drives (or fusion drives) in any system.
Technology moves on.
A fusion drive would be a step down from the SSD that you already have in your ARM based Mac.
I am fairly confident it could not work for the boot partition. The boot drive contains volumes required to boot and verify the system before it would look for the external disk.
It might be possible to create a second partition on the internal disk and create a Fusion Drive with that and an external HDD. This would then be mounted after your login. Even if possible, I think this would be a retrograde step. Better to get a low cost USB SSD (or more expensive Thunderbolt SSD) to store files which don't fit on the internal. Of course, better still (for performance) to get a larger internal SSD!
I am much more confident that you can build a Fusion Drive with an external SSD and an external HDD. Try it!
It might be possible to create a second partition on the internal disk and create a Fusion Drive with that and an external HDD. This would then be mounted after your login. Even if possible, I think this would be a retrograde step. Better to get a low cost USB SSD (or more expensive Thunderbolt SSD) to store files which don't fit on the internal. Of course, better still (for performance) to get a larger internal SSD!
I am much more confident that you can build a Fusion Drive with an external SSD and an external HDD. Try it!
I'm not interested in using a traditional HDD. My Mac Mini has 256GB internally, and I was thinking about getting a Thunderbolt external NVMe drive to try to increase my OS and Application partition. I could always just extend the OS partition across both drives, but I'm not sure if the Thunderbolt drive will run at the same speed as the internal drive (which can't be upgraded). I was thinking that doing the traditional Fusion Drive setup would handle moving the regularly used files to the internal storage for me.
You may be able to prove me wrong, but I seriously doubt you could extend the boot/system partition across two drives.
Since you are stuck with 256GB (clearly you should have got more), leave apps, system and your user home folder on the internal disk and move all files, etc. to the external. You can use symlinks or aliases to make its use fairly seamless.
Even with the best external TB drive it will be slower - but you are unlikely to notice that. Even if you ignore all protocol overheads TB is limited to 40 Gb/s, which lower than the bandwidth of the internal.
There is a considerable overhead with shuffling files to and from the external. This is worth the overhead when the external is a HDD. It would make the whole thing slower than getting a good (expensive) external Thunderbolt SSD.
Fusion Disks are a yesterday's technology purely to make HDDs seem faster. Don't even consider them.
What is your use case and workflow? Fast disks (internal or external) are expensive.
Unless your use is in the professional video area, it is hard to justify a large fast external SSD. If your use is like that, sell the Mini and get Mini or Studio with enough internal SSD for active projects along with external SSDs for backup and long term storage.
I pity the fool who uses an external bus-powered drive as a component of a Fusion Drive. Seriously asking for data loss.
Basically, this:
Also… Apple has instructions on how to move your media libraries:
Change where your music files are stored on Mac
On your Mac, change where your Music files are stored on your computer. You can also manage your files and create folders for better organization.
support.apple.com
Move your Photos library to save space on your Mac - Apple Support
To save storage space on your Mac, you can move your Photos library to a different storage device.
Change where photos and videos are stored on Mac
In Photos on your Mac, store photos and videos in a photo library or outside of it. Copy external files into a library.
support.apple.com
Change Files settings in the Apple TV app on Mac
In the Apple TV app on Mac, set options for folder locations, automatic delete options, and more.
support.apple.com
Move your iMovie for Mac library - Apple Support
To save space on your Mac, you can move your iMovie library to an external storage device.
All ideas involving extending the size of your internal SSD with external storage won't work. Apple Silicon Mac firmware can't read anything but the internal SSD, so there are hoops to jump through if trying to boot from anything else. Apple has implemented a path to boot from a volume completely external to the Mac, but this involves copying a bunch of key system files from that external drive to a hidden volume stored on the internal SSD of the Apple Silicon Mac, and here I'm willing to bet that they haven't bothered to make Fusion Drive a valid target.
Instead of trying to come up with some janky way to merge the external thunderbolt with the internal SSD, I would just use the external drive as additional storage. Unlike some operating systems, macOS doesn't care where third party apps are located, and if written to Apple's guidelines, those apps don't care either, so there's nothing stopping you from just putting some of your apps and/or data on the external.
Are you seriously planning to boot from an hybrid made out of an internal and external drive?
I couldn't think of any better way to turn your system into a ticking time bomb.
All of you make excellent points. This is more of a thought experiment than anything. I'm using one of these for my media libraries (music, photos, etc).
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I also use one for my Time Machine backups.
My Mac Mini isn't really all that short on space, I still have around 40 GB free with all of my usual apps installed. I can always free up more space if I need, I was just considering the options in case I get to a point where that's not feasible.
Thanks for everyone's insight.
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I also use one for my Time Machine backups.
My Mac Mini isn't really all that short on space, I still have around 40 GB free with all of my usual apps installed. I can always free up more space if I need, I was just considering the options in case I get to a point where that's not feasible.
Thanks for everyone's insight.
Pretty sure that, given how much is tied to the internal SSD (unlike any PC and any Intel or PowerPC based Mac, you have no functioning firmware on an Apple Silicon Mac without it), doing a Fusion drive would probably not work. Incidentally, so long as your applications fit on the internal drive, you can always have your data on external drives.
If one part of a Fusion drive is missing, you've got nothing. The drive will just show up as a non-working volume. So if the bootloader can't read the external drive at the EXACT same time as the internal one, before the OS itself is loaded, the whole volume breaks and you've got no OS.
Just use a 'normal' external drive, and move Photos, Music, TV libraries to that. Make sure you've got another drive that is backing up both your internal and external drives, though.
Just use a 'normal' external drive, and move Photos, Music, TV libraries to that. Make sure you've got another drive that is backing up both your internal and external drives, though.
You can completely use a external drive as Systemdrive. I also use an external WD850X in a Acasis Thunderbolt case as my Systemdrive on a Mac Studio.
Speed is around 3000 MB/s and work without any problems. If I’m right, the 256 MB model only work with 1500 MB/s. So the external drive is twice as fast.
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Well... I was about to setup a partition on my internal drive together with a SD card storing my media library as a Fusion Drive on my MacBook Pro M1 Pro. While something like this would have worked on an Intel MacBook it apparently does not work on Apple Silicon based machines. The required utilities [
diskutil cs create/diskutil cs convert] just aren't available. I tried multiple macOS releases including an early beta of Big Sur (oldest public Apple Silicon supporting version of macOS). Only destructive CoreStorage utilities like diskutil cs revert are available. This is even true when the Terminal/diskutil is executed in Rosetta-x86-mode.
A few years back, I had a Fusion Drive on my old iMac, and although the concept was cool, I wasn't a fan due to the performance issues that popped up as the drive usage varied over time. I agree with others who mentioned that a mix of internal and external drives can be risky. It's smarter to use the external drive only for extra storage space for data and bigger applications. With Sequoia, you can set the App Store to download apps directly to an external drive if you install apps from there, which means you don't have to move them manually after installation. Another option is to use the external, larger drive as the main drive, as long as it's an NVME drive for performance (as prices of these drives go down, I would use spinning disks only for backups). I did this with my old M1 mini, and it worked out great. It's definitely better than a Fusion Drive setup between internal and external drives. As far as I remember, this works only with Thunderbolt drives.
Challenge accepted.
I will set up a Fusion drive comprising 1 x 2.5" USB 1TB HDD and 1 x 2.5" USB 120GB SSD.
I will then attempt to install Sequoia on it, along with enough files to exercise the Fusion activity.
We will see how it goes.
I will set up a Fusion drive comprising 1 x 2.5" USB 1TB HDD and 1 x 2.5" USB 120GB SSD.
I will then attempt to install Sequoia on it, along with enough files to exercise the Fusion activity.
We will see how it goes.
Godspeed.
I have nothing but fond memories of Fusion drive.
I have a 2012 Mac mini that has an internal 2TB spinner fused to an internal 250GB SATA SSD for over 10 years now. Works flawlessly. I rescued a friends 2014 base Mac by fusing an external 128GB drive to his 500GB internal. Looked janky but it worked fine for 10 years as well.
I would love to be able to fuse a modern NVME enclosure to a base Mac mini 2024 and beat the Apple tax. A single mounted volume of two devices would resolve the hassles of mounting your home directory on an external drive.
Yeah, with two drives, you square the probability of failure, but with good Time Machine backups, is that really that risky?
First experiment went well.
I used my oldest, cheapest and slowest SSD drive (a Crucial BX500 120GB) and a WD 1TB 2.5" HDD.
The idea was to see how badly it would go.
All went well. Surprisingly well.
The computer booted up a little slower (as you would expect) but not unreasonably so. Applications booted within 1 or 2 seconds as they were stored on the SSD.
This makes a quite workable solution to getting a larger drive system working on a M4 Mac Mini.
However, for a real working solution I think I would use a larger, faster, more modern SSD.
I also have a Samsung T7 SSD, which when plugged in via one of the Thunderbolt ports is very fast (700 ~ 1000 Mb/s transfer). Someone mentioned using a drive like that to make a fusion drive with the internal Mac Mini SSD.
However, as others have found, a T7 drive plugged directly, or via a hub, into a Mac Mini gets too hot and needs a cooling solution. I have used a little USB powered fan to keep mine cool and have some cooling fins on order for mine.
I used my oldest, cheapest and slowest SSD drive (a Crucial BX500 120GB) and a WD 1TB 2.5" HDD.
The idea was to see how badly it would go.
All went well. Surprisingly well.
The computer booted up a little slower (as you would expect) but not unreasonably so. Applications booted within 1 or 2 seconds as they were stored on the SSD.
This makes a quite workable solution to getting a larger drive system working on a M4 Mac Mini.
However, for a real working solution I think I would use a larger, faster, more modern SSD.
I also have a Samsung T7 SSD, which when plugged in via one of the Thunderbolt ports is very fast (700 ~ 1000 Mb/s transfer). Someone mentioned using a drive like that to make a fusion drive with the internal Mac Mini SSD.
However, as others have found, a T7 drive plugged directly, or via a hub, into a Mac Mini gets too hot and needs a cooling solution. I have used a little USB powered fan to keep mine cool and have some cooling fins on order for mine.
I wouldn't be so sure about that until you've actually tested booting an Apple Silicon Mac from a Fusion drive composed of its internal SSD and an external.
Apple Silicon's early boot process requires that certain files (the macOS kernel, kernel extensions, and firmware files) be present on a non-Fusion volume on the internal SSD. This is an absolute requirement, because Apple Silicon firmware has no drivers for accessing any kind of disk other than the internal SSD.
The hack Apple uses to provide the appearance of being able to boot from an external drive is that when you install macOS on an external (or later, do a software update on that external), copies of the critical files are made inside a hidden partition on the internal SSD. Everything boots from the internal SSD until the macOS kernel is running. It has enough drivers to be able to access externals, so it is able to mount the external drive (or fusion drive, in your case) and continue booting from it.
It's possible that Apple has made sure all this still works with a Fusion Drive of the internal SSD and external by partitioning some non-Fusion space on the internal. But it is not guaranteed - they may not have decided to cover this case in their design or testing.
You may be right. Given that I currently have a fully working M4 Mac Mini, I think I will leave it as it is, until I need to rebuild it.
However...
I have been using a perfectly functional all-external Fusion drive for the last couple of days.
The initial experiment using my "oldest, cheapest and slowest SSD drive (a Crucial BX500 120GB)" drive failed when I tried to up grade from OS 15.1.1 to 15.2. Something got corrupted so I had to start again.
Using a Seagate Fast SSD and the same HDD as previous, it has all worked very nicely. All the applications are now opening up from the SSD and the users' data files are on the HDD.
It does take a little longer to boot up, perhaps because of what mr_roboto was saying. It may take time for the system to find the external drive and boot from it.
But, once booted up it does all work well.
I have been using old, slow drives to see how that worked. However, it you wanted a real, working system, I would strongly suggest the fastest drives (SSD and HDD) with the largest cache on the HDD you can get your hands on.
So, to answer the OP's question - Yes you can, and it works, and it works better than you would think, especially if you use good quality drives.
The original poster asked for information but you are answering with an opinion. There is a myriad of reasons why someone might want to do this (and none of them concern you). If you can’t (or won’t) answer the question in a constructive manner, I suggest you move on.
I was looking for information in advance of maybe doing the same thing, and there seems to me a lot of strange answers in this thread, which is one of the top results so I wanted to correct some of it:
Firstly, a number of M1-4 macs such as the iMacs don't offer internal storage beyond 1 tb, and Apple famously overcharges for storage, so the idea that people should have just buy what they need at the time is silly – what if you want an iMac but need 2tb? When the only option is added disks then a Fusion drive becomes something to consider.
Second, in terms of redundancy if you're splitting your data between two disks then you have no redundancy in that case either – while you won't lose all of your data if one fails compared to the Fusion drive, that's still not exactly acceptable as you've probably still lost data that you need anyway. You should have a regular backup (such as via Time Machine) in either case as you have no true protection otherwise.
Third, Fusion drives do not need to be an SSD + HDD, you can use two SSD if you want. This is what the OP and myself are considering, since it's possible to buy high capacity SSDs for a fraction of what Apple charges if storage is your priority and they're hardly what I'd call slow, just might not be as fast as the internal SSD, though that's not necessarily the case either (the smaller internal SSDs aren't as fast as the larger ones, and Thunderbolt can outperform them on sustained speed).
Fourth, M1-4 macs can boot from external drives, you just have to enable the option from recovery mode, and things like firmware are not stored on the drive. You need a drive for the EFI, preboot and macOS partitions, recovery and VM are optional (but recommended). As long as your Mac was set to allow external booting you can supply all of these from an external drive if you really want to, and thus boot from it, but it's disabled by default as potentially a security risk. Even without an internal drive, or an erased one, it's possible to boot into a recovery environment, but it'll be over a network connection so much, much slower.
Fifth, the tools for creating Fusion drives do still exist – while you can technically still do it using diskutil cs, you probably don't want to (APFS is preferred now). You can actually create Fusion drives using diskutil apfs now too, you just need to specify more than one device – I don't believe there's any way to "extend" an existing APFS volume into a Fusion drive. The command you want is diskutil apfs createContainer as this allows you specify which device is the main (fastest) and which is the secondary (slower) device. The documentation even specifically references using this with an external device, as you're recommended to use this command since macOS can't always determine the speed characteristics of an external drive.
Sixth, while using an external drive isn't ideal, there's nothing fundamentally wrong with doing so, you just need to make sure the drive is connected at startup so the various boot processes can find it, there's no race condition – if it's connected and working it'll be found, and even with a slower HDD the system will just wait for it to spin up. All the firmware cares about is if the drive can be found or not, it's not looking for excuses to fail.
Setting up for a Fusion drive seems like it's about the same as it is now – you'd need to reboot into recovery mode, and use that to erase the disk, then use Terminal to run
(swapping disk numbers for the correct ones from diskutil list), then reinstall onto the new APFS disk created from the two drives. NOTE: I've updated this to refer to a partition ID for the argument to -main as if you're using an internal disk it may already be partitioned for recovery etc., so you want a new container replacing the old main container, and combining it with an external disk. Always triple check the disk ids you give to make sure you're the reference the correct partition and/or disk.
Should work just fine, with the data splitting being completely invisible to the user – just make sure you have a Time Machine drive setup (which every Mac user should have regardless).
Firstly, a number of M1-4 macs such as the iMacs don't offer internal storage beyond 1 tb, and Apple famously overcharges for storage, so the idea that people should have just buy what they need at the time is silly – what if you want an iMac but need 2tb? When the only option is added disks then a Fusion drive becomes something to consider.
Second, in terms of redundancy if you're splitting your data between two disks then you have no redundancy in that case either – while you won't lose all of your data if one fails compared to the Fusion drive, that's still not exactly acceptable as you've probably still lost data that you need anyway. You should have a regular backup (such as via Time Machine) in either case as you have no true protection otherwise.
Third, Fusion drives do not need to be an SSD + HDD, you can use two SSD if you want. This is what the OP and myself are considering, since it's possible to buy high capacity SSDs for a fraction of what Apple charges if storage is your priority and they're hardly what I'd call slow, just might not be as fast as the internal SSD, though that's not necessarily the case either (the smaller internal SSDs aren't as fast as the larger ones, and Thunderbolt can outperform them on sustained speed).
Fourth, M1-4 macs can boot from external drives, you just have to enable the option from recovery mode, and things like firmware are not stored on the drive. You need a drive for the EFI, preboot and macOS partitions, recovery and VM are optional (but recommended). As long as your Mac was set to allow external booting you can supply all of these from an external drive if you really want to, and thus boot from it, but it's disabled by default as potentially a security risk. Even without an internal drive, or an erased one, it's possible to boot into a recovery environment, but it'll be over a network connection so much, much slower.
Fifth, the tools for creating Fusion drives do still exist – while you can technically still do it using diskutil cs, you probably don't want to (APFS is preferred now). You can actually create Fusion drives using diskutil apfs now too, you just need to specify more than one device – I don't believe there's any way to "extend" an existing APFS volume into a Fusion drive. The command you want is diskutil apfs createContainer as this allows you specify which device is the main (fastest) and which is the secondary (slower) device. The documentation even specifically references using this with an external device, as you're recommended to use this command since macOS can't always determine the speed characteristics of an external drive.
Sixth, while using an external drive isn't ideal, there's nothing fundamentally wrong with doing so, you just need to make sure the drive is connected at startup so the various boot processes can find it, there's no race condition – if it's connected and working it'll be found, and even with a slower HDD the system will just wait for it to spin up. All the firmware cares about is if the drive can be found or not, it's not looking for excuses to fail.
Setting up for a Fusion drive seems like it's about the same as it is now – you'd need to reboot into recovery mode, and use that to erase the disk, then use Terminal to run
Code:
diskutil apfs createContainer -main disk0s2 -secondary disk1Should work just fine, with the data splitting being completely invisible to the user – just make sure you have a Time Machine drive setup (which every Mac user should have regardless).
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Have you done this? Do all the APFS volumes end up in the Fusion container or are some (e.g. VM, Recovery, Preboot) in an APFS container just on the internal SSD?
You don't need to boot into Recovery Mode to create a Fusion drive from external drives.
This is how I have done it successfully several times, both for my aging Intel iMac and my new M4 Mac Mini --
- Format each disk using
Bash:
sudo diskutil partitionDisk disk(n) 1 gpt jhfs+ (name) 100% - Create the Fusion drive using
Bash:
sudo diskutil apfs create (disk1name) (disk2name) (FusionDiskName- That works if the system can identify which disk is the fast SSD and which is the slow HDD. If it can't, you need to use
Code:sudo diskutil apfs createContainer[-main] device [-secondary] [device] sudo diskutil apfs addVolumecontainerReferenceDevice filesystem name
- That works if the system can identify which disk is the fast SSD and which is the slow HDD. If it can't, you need to use
The exception is the special areas that are on the M(series) Macs that it uses to initiate booting from.
I think it could work, and I think it could be useful, but yes, the proof is in actually doing it. It's on my list of things to try sometime (but not very high). : )
I don't see why ALL of the volumes have to be on the Fusion container for this to be useful. Why does Preboot, for example, need to be in the Fusion container for this the idea to be useful, as long as the Data partition is.
I don't see why ALL of the volumes have to be on the Fusion container for this to be useful. Why does Preboot, for example, need to be in the Fusion container for this the idea to be useful, as long as the Data partition is.