Once and for all: Does MacOS Mojave work with Fusion Drives?

[blackdogaudio]

Got a late 2014 5K 1 TB Fusion drive iMac here with zero issues during Mojave's release and conversion to APFS. The process took about an hour with a few reboots where nothing showed on the display for quite a few minutes. Just had to be patient and not panic ;-)

 

[giffut]

No, don´t do it. APFS has problems in general, but with a fusion drive you will experience failure for sure. It is not worth it. Mojave runs fine with HFS+ formatted disks.

 

[Rayamedia]

No problems updating but it seem much slower on my 2015 5k 27 with 2TB fusion. Tried every thing but I can see application icons get loaded and Motion takes about 2 minutes to load. Other apps load fast so I am a bit stumped. Seems really slow if I have multiple things going on. eg loading 2 apps at once. Would be a pain to reformat the drive but I am considering it.

UPDATE
It was Intego virus barrier. Turned off realtime scanning early on but I had to turn it off and restart to see the difference.

Night and day performance. Now fusion is performing as good or better than on High Sierra

All my software works perfectly on Mojave. Except Moho pro which has a few glitches. Very good upgrade. Very solid for me

 

[giffut]

Harddrive usage for a system drive is not recommended in general, independend of the os. But Apples fusion drive concept was a bandaid when SSD prices where very high. That they still sell it nowadays is a disgrace and can only explained that they want to save any margins on component costs regarding cheap and slow HD storage. This was obvious when they reduced the SSD portion of the fusion drive in iMacs from 128GB standard to 24GB on the entry level iMacs.

A fusion drive is not good nowadays: It doubles I/O complexity and risk of a drive failure to data loss, especially when used as system/boot drive. Use the fusion drive for data/backup only.

Get an external SSD via USB3/C or thunderbolt port and boot your machine form there. It´s much cheaper than getting a new mac with an adequate SSD. They are ridiciously overpriced in terms of cost/GB and can´t be repurposed for usage in another machine.

 

[fisherking]

No, don´t do it. APFS has problems in general, but with a fusion drive you will experience failure for sure. It is not worth it. Mojave runs fine with HFS+ formatted disks.

"problems in general"? you will experience 'failure for sure"? what are your sources for this important information?

 

[giffut]

APFS has severe performance problems on spinning disks, because it was made for SSD firsthand. The fusion drive structure therefore complicates I/O operations in many ways.

APFS is still not deeply tested enough for all its quirks and bugs. There are issues regarding data consistency. This also correlates to the problems the bridge os/T2 processor has. It controls all encryption related processes but it is prone to errors not yet fully understood, especially in combination with APFS.

 

[rbart]

APFS on 5K 1TB Fusion drive (24Gb SSD) works perfectly for me.
It's faster than HFS+ on the same machine, I think APFS features help the fusion drive system to optimize the files to put on the SSD part.

 

[nkarafo]

I have an iMac 2015 27" with fusion drive. I have make two partitions in the main ~1tb drive. Will I have a problem with Mojave? Does it really worth it? Thank you.

 

[esatamacmodular]

I have an iMac 2015 27" with fusion drive. I have make two partitions in the main ~1tb drive. Will I have a problem with Mojave? Does it really worth it? Thank you.

I have a 2013 iMac 1TB (128GB) fusion. It seems there are mixed feelings about whether it will work. I wonder:

is it an option keep HFS+ formatting?
what about 10.14 and bootcamp with windows 10?

 

[VArase]

This is my story too. Slower than molasses. No network - ethernet or wifi (missing drivers). I ran back to High Sierra from a Time Machine backup.

Feel terrified about trying that upgrade again.

Did either one of you try formatting the disk, lay down Mojave, convert to APFS, then restore everything but the system?

Just curious, but that's what I'd do.

 

[jerwin]

I had a real scare trying to reinstall mojave on my imac 5k with fusion drive.

My imac 5k was experiencing all sorts of weird errors, and would not install the latest update. So, with some trepidation, I tried to restore my drive using Time Machine. Many hours later, I ended up with a broken machine.

The mac booted up half way, but then stopped with that last icon--the no symbol
Apparently, Apple thinks error messages should be stylish, rather than informative.

The only method that worked was to install Mojave (by booting my Time Machine drive), and then migrating all my data.

I think the problem might have been related to a misconfigured Apple supplied utility mistakingly formatting my fusion drive as HFS+, rather than as the file system compatible with Mojave (APFS).

Anyway, I got very little sleep last night.

 

[TehFalcon]

No problems installing and using APFS on the 1TB Fusion drives in both of my 2014 Mac Minis.

 

[ultradk]

This is my story too. Slower than molasses. No network - ethernet or wifi (missing drivers). I ran back to High Sierra from a Time Machine backup.

Feel terrified about trying that upgrade again.

Do fusiondrive works well with High Sierra?

 

[CoastalOR]

Do fusiondrive works well with High Sierra?

OT since this thread is about fusion drives and Mojave.
High Sierra does not automatically convert the fusion drive to APFS (like Mojave does). The fusion drive will remain HFS+ when installing High Sierra, but you can still upgrade and run High Sierra on a fusion drive. Just make sure you have a good backup before installing any new macOS in case you want to downgrade back.

 

[esatamacmodular]

I'm also having trouble with this for my iMac 2013 1TB+128SSD fusion (original OEM install). Never installed bootcamp before but just installed Mojave (coming from 10.9). Now a bootcamp attempt will not complete windows 10 partition successfully. I have tried some tricks with disassociate/remove time machine backup drive, delete local time machine snaps (via terminal) and then disk repair. Start bootcamp install sequence again ... nope same problem. I'm using 16 GB USB 2.0 thumb drive as well for install (per apple directions).

 

[liorp]

Update: I did it!

After reading all of your insightful comments and doing some thinking on my own, I backed up everything I cared about and upgraded to macOS Mojave. My Macintosh HD was converted to APFS:
And everything has been perfectly fine so far. Thank You all for your feedback!
At this point, this thread is out of my hands and looks like a wonderful place for ya'll to tell your success and horror stories about your upgrades to Mojave. That said, thank you again!

 

[haxAT]

Took 24!! hours to convert the 3TB Fusion drive of my 27" Imac (Late 2013) to APFS ... I did it manually in recovery mode. Seemed like it stopped but completed after a LOT of time.

 

[Jonathan Swerdloff]

YMMV but I discovered an errant *nix file that caused all of my troubles. Once renamed to .bak it all seems to have worked. The file was sysctl.conf in /etc/ just in case this comes up for others.

 

[LuisN]

Easiest way to build Fusion Drives in Mojave:

https://apple.stackexchange.com/questions/309739/apfs-container-over-multiple-physical-disks#

Read it and follow the steps

Mojave does indeed work (very well) in fusion drives

 

[dirt farmer]

Update: I did it!
View attachment 804307
After reading all of your insightful comments and doing some thinking on my own, I backed up everything I cared about and upgraded to macOS Mojave. My Macintosh HD was converted to APFS: View attachment 804309
And everything has been perfectly fine so far. Thank You all for your feedback!
At this point, this thread is out of my hands and looks like a wonderful place for ya'll to tell your success and horror stories about your upgrades to Mojave. That said, thank you again!

You ignored the Chicken Little's. Good for you!

 

[gardenminion]

I updated my 2012 Mac Mini with DIY Fusion Drive to Mojave some time ago without a hitch, at first. It booted, worked as expected (I think) and I had it running for some time. The it rebooted, and since then it freezes on the Apple logo instantly at boot. I've done extensive poking and prodding, reading up on forums and what not, but I've been unable to master the issue. I've reinstalled Mojave again, and it boots and works until the first reboot. Then it's no go until I reinstall the OS again. The log shows it goes to kernel panic very early in the boot process. It wasn't until I found this thread I figured it might have something to do with my DIY fusion drive. I haven't tried anything in a few weeks, but just reinstalled again and will try to figure out what my next step is. Apparently it didn't automatically convert to APFS because it says it's still HFS+. Should I try converting to APFS or do a format, clean install and restore from Time Machine?

 

[liftin]

I have had a two-month nightmare with Mojave and my late-2014 iMac 27”.
Mojave wouldn’t install on my OEM fusion drive - found problems - so I installed a SATA SSD from OWC. Still problems. Took to apple store. They identified a bad RAM module and installed Mojave for me. Replaced the RAM.

The machine was never reliable thereafter. Ran OK for short intervals before going into molasses mode for most of the time. Disk utility wouldn’t even make it through the volume. Tried to reinstall Mojave and made it worse (woudln’t Complete the process). Eventually it woudn’t boot any more, after hours logged w/apple support.

Was back at apple store yesterday, and the techs there made this jaw-dropping suggestion:
This iMac is designed to work with a fusion drive. So you MUST replace the original HD with an actual HD, not an SSD, and fuse the drives. This seems nuts to me, as you should be able to run from any legit volume — USB external, whatever. Anyone heard this restriction before? Any logic there? Thank you....

 

[3rdShore]

I understand this is an older thread, but I've searched extensively and haven't yet found the best path forward. I'm seeking recommendations.

I'm currently running macOS High Sierra on a late 2012 Mac mini with a self installed SSD and the original HDD NOT setup as a Fusion drive. I finally decided I'd prefer the Fusion setup for the sake of simplicity when the SSD couldn't handle the size of my current iPhone backup (and I don't want to jump through the hoops of configuring the backup to an external for the same sake of simplicity).

My question is whether I should:
-Create the Fusion in High Sierra and then update to Mojave?
-Update to Mojave and then create the Fusion drive (not sure if it can also be done DURING the update)?
-Create the Fusion drive in High Sierra, and don't update to Mojave?

Of course any other suggestions are appreciated as well.

 

[ericsvl]

Yes. Have a 3TB Fusion drive in a 2013 27" iMac, NO issues.

Lucky you. Same config, 27p / 3To fusion drive... and my iMac is terribly slow (1min30) to boot on a fresh Mojave install, while, if I boot from an external SSD (USB3), it takes 40sec.
When I have completely reinstalled all my applications and account from Time Machine, +2min to boot , and 3min30 with FUSE activated for using pCloud... and this is only slowness...
I think I'll go with the solution of the external SSD.

Steve, Come back!
[doublepost=1553702296][/doublepost]

This iMac is designed to work with a fusion drive. So you MUST replace the original HD with an actual HD, not an SSD, and fuse the drives. This seems nuts to me, as you should be able to run from any legit volume — USB external, whatever. Anyone heard this restriction before? Any logic there? Thank you....

So you and I have to use High Sierra!? Unfortunately, my mails are converted to Mojave Mail, and I no longer have a backup from High Sierra

 

[lshaner]

I have had a two-month nightmare with Mojave and my late-2014 iMac 27”.
[snip]
Was back at apple store yesterday, and the techs there made this jaw-dropping suggestion:
This iMac is designed to work with a fusion drive. So you MUST replace the original HD with an actual HD, not an SSD, and fuse the drives. This seems nuts to me, as you should be able to run from any legit volume — USB external, whatever. Anyone heard this restriction before? Any logic there? Thank you....

Apparently that is the bonafide position that Apple has taken. :-(

https://support.apple.com/en-us/HT209158