Mojave on Fusion drive


CLS7

macrumors member
Jul 13, 2016
68
24
Malmoe, Sweden
Does anyone run Mojave on iMac with Fusion drive. Did it make the transition to APFS? How is it performance wise now?
I run Mojave beta on a iMac 27" late 2015 with 1GB Fusion drive. When I upgrade from High Sierra to Mojave it convert the disk to APFS automatically.

It feels that I have better performance in Mojave compare to High Sierra.
 

sumo.do

macrumors regular
Mar 12, 2014
155
32
Australia
Does anyone know if installing Mojave is the only way to get APFS running on a fusion drive? I have two pre 2012 Mac minis that cannot run Mojave but have a fusion drive in HFS+ still. I know Mojave will support fusion but does anyone know if Apple is going to come up with (or has come up with) something for the Macs with fusion drives caught in High Sierra world?

Yes I know the 2011 Mac minis did not have fusion drives.

I just wanna know if Mojave is the only option.

Any terminal tricks?
 

chrfr

macrumors G3
Jul 11, 2009
8,185
2,514
Does anyone know if installing Mojave is the only way to get APFS running on a fusion drive? I have two pre 2012 Mac minis that cannot run Mojave but have a fusion drive in HFS+ still. I know Mojave will support fusion but does anyone know if Apple is going to come up with (or has come up with) something for the Macs with fusion drives caught in High Sierra world?

Yes I know the 2011 Mac minis did not have fusion drives.

I just wanna know if Mojave is the only option.

Any terminal tricks?
Yes, Mojave is the only way to run the OS from APFS on a Fusion Drive.
 

sumo.do

macrumors regular
Mar 12, 2014
155
32
Australia
Yes, Mojave is the only way to run the OS from APFS on a Fusion Drive.
So my only options for my 'non-Mojave' macs is to either de-fuse and run the OS on APFS on the SSD (stand-alone) in High Sierra or keep the fusion and keep it in HFS+ in High Sierra till death do us part?
 

chrfr

macrumors G3
Jul 11, 2009
8,185
2,514
So my only options for my 'non-Mojave' macs is to either de-fuse and run the OS on APFS on the SSD (stand-alone) in High Sierra or keep the fusion and keep it in HFS+ in High Sierra till death do us part?
Just keep it on HFS+. You're not really missing anything.
 

sumo.do

macrumors regular
Mar 12, 2014
155
32
Australia
Just keep it on HFS+. You're not really missing anything.
Yeah I know. I have newer Macs running APFS. Nothing strikingly different to the human eye. But I just feel sorry for my old Mac mini 2011 server quad core i7. It was beast for it's time. Maxed out with 16GB of Corsair Vengeance RAM and its Samsung 840 Pro. It still throws punches. And now it is living out its days handicapped. Living out its last days in the pastures in the High Sierra mountains. It is just so sad to watch it wither away... sigh.. I'm gonna go and eat some chocolate...
 
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Kawawolf

macrumors newbie
Jan 24, 2018
20
5
Upstate NY
So if I understand some posts correctly updating my 2017 imac with a fusion drive to Mojave is probably going to format it to APFS automatically?
 

torpidlittle

macrumors newbie
Oct 24, 2014
10
1
Does anyone know if installing Mojave is the only way to get APFS running on a fusion drive? I have two pre 2012 Mac minis that cannot run Mojave but have a fusion drive in HFS+ still. I know Mojave will support fusion but does anyone know if Apple is going to come up with (or has come up with) something for the Macs with fusion drives caught in High Sierra world?

Yes I know the 2011 Mac minis did not have fusion drives.

I just wanna know if Mojave is the only option.

Any terminal tricks?
As stated by Craig Federighi himself, this feature will only be supported in Mojave...unfortunately!

" Hi Simon, This feature (APFS for Fusion Drive) will be available only in Mojave. HDD and Fusion drives will continue working well with HFS+ / CoreStorage in High Sierra."

Thanks!

- craig

But, take a look at this: http://dosdude1.com/mojave/

Maybe it could be an alternative solution for you old macs ;)
 
Last edited:

sumo.do

macrumors regular
Mar 12, 2014
155
32
Australia
As stated by Craig Federighi himself, this feature will only be supported in Mojave...unfortunately!

" Hi Simon, This feature (APFS for Fusion Drive) will be available only in Mojave. HDD and Fusion drives will continue working well with HFS+ / CoreStorage in High Sierra."

Thanks!

- craig

But, take a look at this: http://dosdude1.com/mojave/

Maybe it could be an alternative solution for you old macs ;)
That is a lot of unsupported options there. :confused:

Mojave on an unsupported mac with an unsupported fusion drive for that model of Mac mini with an unsupported format of APFS for the Fusion drive.

I think I'm gonna go old school and keep it High Sierra with a Fusion drive in HFS+ flavour.
 

NZBred

macrumors newbie
May 28, 2013
22
6
I can confirm that my iMac late 2012 with 1T FD is now running Mojave and my drive is now APFS. No issues. Speed is almost the same as before.
I recently installed Mojave on my late 2012 Mac Mini and so far, everything works fine. The only issue I did experience was slow boot times i.e 2-3 minutes, however, after resetting the SMC controller, the average time is around 20-30 seconds...
 

Easttime

macrumors 6502a
Jun 17, 2015
565
382
My 2014 Mac mini’s fusion drive went APFS automatically when I upgraded to Mojave. No performance issues. In fact I noticed nothing different at all.
 
Last edited:

Starfia

macrumors 6502a
Apr 11, 2011
607
314
According to Disk Utility, the transition was successful (yay).

I hadn't noticed any performance differences until you brought it up, which prompted me to try opening a few folders with many images – I remembered the icon previews sometimes taking around a second to load in those situations when scrolling through a Finder window. This time, it was near-instantaneous; maybe a few frames of unloaded icon previews before they showed up. I'm not sure whether that can be pinned to the file system specifically, but it at least seems like an improvement in Mojave.
 

ultradk

macrumors member
Oct 1, 2009
32
5
Denmark
I did some playing with Mojave in the last few days here.. I went back to Sierra!..

I guess they were to early with Mojave, it's largest - even after clean install..
Maybe it's my iMac 21.5" late 2012 with fusion drive. I did test High Sierra when that came out, same problems, even if APFS is supported for fusion drives in Mojave - no difference for me.

Just got Sierra back and everything is working fine.

Already thinking iMac 27 if there come new models around the corner.. but with fusion drive - I don't know..

Also wait to see if there will be any updates that could help..
 

Foxer

macrumors 65816
Feb 22, 2003
1,250
21
Washington, DC
My late-2012 iMac with 3TB fusion won't take to Mojave. I've tried installing several times since the public betas and every time there are problems. Frequently it won't complete the installation. On the occasions when it does, I get numerous errors, random hardware (mouse and keyboard -- both Apple) incompatibility and slow (I mean snail, unusable) slow performance. I've had to go back to High Sierra each time and on at least three occasions I had to go into Terminal and rebuild the drives into the single fusion volume. I'm really confused that this doesn't seem to be common.
 

phuocsandiego

macrumors member
Jun 19, 2012
79
4
Mac OS Mojave on my late 2014 iMac with a 1TB Fusion Drive is HORRIBLE. I don't know what other people are smoking, but it's a huge downgrade from High Sierra. Maybe I have to reset the SMC controller like the other poster mentioned? I have no idea but it's minutes to boot now consistently rather than seconds. Even after entering my password, loading all the same startup items continue for 3+ minutes. Honestly, it's a terrible downgrade for me. The only benefit I see if the dark theme. That's it. I can't tell what APFS is doing for me, except to give me worse performance.

Maybe my situation is different but it sucks.
 
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avelo

macrumors newbie
Nov 26, 2018
1
0
Hi.

I got a iMac late 2015, 16gb ram, 1gb Fusion Drive. Upgrading to Mojave has some issues for me. After logging in, it takes more than usual to open every application that I press. Telegram takes the longest, like 4 min to open fully, chrome 30-40s etc. This didn't happened before. I was using Sierra because of the issues of fusion drive on High Sierra.

I do not have many applications that start on boot, just chrome sync and istat menus. I removed all of them but still the same.

:/
 

Person Man 2

macrumors newbie
Nov 4, 2015
19
35
I also had terrible performance with my 2014 5K Retina iMac 27" with Fusion drive after updating to Mojave. At first everything seemed to work ok but it was quite slow. Then I started having application crashes and random kernel panics. I could restart the system at first, but then I noticed that certain applications would not launch and then when I tried restarting the system it wouldn't boot. I booted into recovery mode and used Disk Utility to check the drive and it came up with a bunch of errors. A little Googling turned up others who upgraded their Fusion machines from High Sierra having the same types of errors.

Fortunately I had backups so I wiped the drive and did a clean reinstall of Mojave and all my applications and copied my data over from the backup. No more disk errors but everything was slow. Boot times of 3 minutes, and applications taking a long time to start. Performance of Parallels was appalling. It would take Windows 5 minutes to boot and an installation of the Parallels Tools after updating the Parallels application took a half hour. Googling the issue turned up nothing, other than reports of the system being temporarily slow after updating because system processes were running in the background. But I had been using Mojave for about a month on this machine and so those processes had long since finished, and everything was still slow.

Since Mojave changes the way a Fusion drive works so the SSD is used as a cache, I speculated that the overall slowness was due to the fact that the operating system and Windows and applications are loading from the hard disk. I decided to test this by cloning my setup (with SuperDuper!) to an external SSD and booting from that. It was an immediate improvement. The computer booted quickly and applications started quickly. The sluggishness was gone.

My next step was to split the Fusion drive into separate SSD and hard drive. This was harder than I anticipated, because Mojave does not use Core Storage to combine the two like older versions did. So none of the online tutorials about how to split a Fusion drive would help me. If I had time I could have spent time reading man pages to figure out how to do it from the command line in Mojave but I didn't so I ended up doing it like this instead:

I wiped the internal volume and rebooted the machine with Internet Recovery. Since my iMac originally shipped with OS X 10.8.2, that is what loaded from the internet. Mountain Lion is before APFS, so it didn't recognize the drive. Upon opening up Disk Utility it popped up a dialog box saying the Fusion drive appeared "damaged" and offered to "re-fuse" it for me. I presume that if I had said yes it would have set up a new Core Storage Fusion drive. I said no, which left both drives separate and then I could partition and format both as separate HFS+ volumes. I then booted into the Mojave clone from the external SSD and used the Mojave installer to install a fresh copy of Mojave on the internal SSD. In the process that drive was converted to APFS (it also sets up the hidden partitions on the drive that the cloning process could miss). I left the internal hard drive as HFS+. I moved my documents, Parallels virtual machine, and my photo library to the spinning hard drive, which left plenty of space on the SSD for the operating system and applications. I then cloned the external SSD (with the documents, etc removed) back to the internal SSD.

The machine has been running great since then. This is my work machine, so I can get by with using a 128 GB SSD for the main partition and the regular hard drive for documents and data. When the time comes to replace it I will only have SSD storage (probably 1 TB).

I know this was long, but others might benefit from my experience.

TL;DR. My Fusion drive was running slowly so I split it into the separate components, put the OS and applications on the SSD formatted as APFS and my documents and data on the spinning hard drive formatted as HFS+ and everything is running smoothly under Mojave now.
 
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