What about the FUSION Drives?

[Clix Pix]

Seems to me that it would make sense then for people to convert their external HDDs and external SSDs to APFS also, in order to have consistency with the computer's internal drive. I have converted my external HDDs to APFS and there are no issues with any of them.

 

[Elembytes]

High Sierra is compatible with Fusion Drives. I have multiple Mac minis running High Sierra with Fusion Drive. The difference with Mojave is that APFS is going to be compatible with Fusion Drives.

You can start with a Fusion Drive on High Sierra today and migrate to Mojave at a later date.

Got it! Thanks! This is more clear to me now. So I will go ahead and upgrade from Yosemite to High Sierra while I still can. Then Mojave will change the file system for ALL of us no matter what. Thanks!
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I think you're mixing things up quite a bit here. Either that or I don't really understand what you're trying to say. APFS and High Sierra are not synonymous - High Sierra can easily run off of HFS+ partitions as well. And since APFS is only supported for SSDs in High Sierra the installer is never going to attempt to put APFS on your iMacs Fusion Drive simply because it isn't supported yet. This means that when attempting to install High Sierra on a Fusion Drive or regular hard disk drive the volume is NOT converted to APFS but remains formatted as HFS+ (Mac OS Extended (Journaled)). Case in point: my iMac with FD is running High Sierra on a regular HFS+ volume while my 12" MacBook is running High Sierra on an APFS volume.

With Mojave, this is going to change. HFS+ is no longer supported in 10.14 at all, which means that EVERY SINGLE DRIVE - be that SSD, Fusion Drive, or HDD - is going to get converted to APFS whether you like it or not. And unlike in High Sierra the undocumented switch to prevent this from happening no longer seems to be working. Thus, there is no way to run 10.14 off an HFS+ drive.

In other words: waiting for Mojave will get your drives converted to APFS for sure, and there doesn't seem to be a way to opt out. Installing High Sierra, on the other hand, is not going to f*** up your file system but leave everything as is.

Nope you got what I was saying and your response helped me to better understand things NOW and in the future so this is great! Thank you!!!! I will go ahead and upgrade from yosemite to High Sierra while I still can and know that if I upgrade to mojave it will change the filesystem for all of us regardless of drive types, other then externals. Thank you so much for your help!

 

[SoYoung]

I just want to know if APFS will affect performance on a fusion drive in everyday usage and when I play games. My fusion drive is 1TB with only 24GB of SSD storage.

 

[mj_]

No, it won't affect performance at all. Especially not gaming performance. What are you expecting to happen anyway? It's a file system, not a genie in a bottle

 

[stooovie]

Of course it will affect performance, probably in major way. APFS is designed for SSDs, it does a lot of file segmentation in order to provide features like incremental writes (only write a portion that's been modified). Any mechanical HDD is really bad at lots of random I/O like this. Performance WILL be worse on Fusion drives with APFS. Of course, that doesn't mean FPS will drop - that's CPU and GPU bound. But everyday file operations like launching apps will suffer.

 

[SoYoung]

Damn. I really hope we’ll have the choice to convert it or not otherwise i’ll Simply not updating. No way I want to slow down my computer.

 

[DennisdeWit]

This is not true. I have installed Mojave on my Fusion Drive and I noticed the files are copying much faster. Nothing is sluggish or slow or whatever. I figured the files are copying even faster than on HFS.

In ny opinion you could TRY if you want, or wait till a later beta/release when many have proven it works.

My iMac is with Apple Care. Should APFS really break the hard disk over the next 2 years, I’ll still be eligible for a new one. I make backups so I don’t really see the issue much.

 

[SoYoung]

This is not true. I have installed Mojave on my Fusion Drive and I noticed the files are copying much faster. Nothing is sluggish or slow or whatever. I figured the files are copying even faster than on HFS.

In ny opinion you could TRY if you want, or wait till a later beta/release when many have proven it works.

My iMac is with Apple Care. Should APFS really break the hard disk over the next 2 years, I’ll still be eligible for a new one. I make backups so I don’t really see the issue much.

Thanks for the info. Is it easy to go back on a back up formatted to HFS is you are on APFS?

 

[DennisdeWit]

Thanks for the info. Is it easy to go back on a back up formatted to HFS is you are on APFS?

No. Forget about that. Rolling back to HFS will be a real pain due to the different partition lay-out and containers. I have done that at High Sierra when they had a bug and I already converted it to APFS. It was a dumb thing to do. I had to first restore the full hard disk layout manually, than re-link all the parts in the partition table and then revert back by Time Machine.

If you’re planning to run a beta on your daily driver machine and are dependent of your files, don’t do it. All my important files are backupped on a Synology (raw files, not just a Time Machine backup) and so I dared to do it.

I have no regrets, it works fine and faster, but it’s up to you to take the gamble. After all, it’s still a very first beta.

 

[antonypg]

I was looking through some of the WWDC videos from last year. The APFS version of Fusion is meant to be much smarter/faster than the HFS version because it will look at file types more intelligently. All file metadata will be moved to the SSD, which will speed up file browsing/searching, plus it should more intelligently move applications towards the SSD and media files onto the HDD.

 

[mszilard]

No. Forget about that. Rolling back to HFS will be a real pain due to the different partition lay-out and containers. I have done that at High Sierra when they had a bug and I already converted it to APFS. It was a dumb thing to do. I had to first restore the full hard disk layout manually, than re-link all the parts in the partition table and then revert back by Time Machine.

If you’re planning to run a beta on your daily driver machine and are dependent of your files, don’t do it. All my important files are backupped on a Synology (raw files, not just a Time Machine backup) and so I dared to do it.

I have no regrets, it works fine and faster, but it’s up to you to take the gamble. After all, it’s still a very first beta.

Restoring an apfs to hfs is quite painless, just start in recovery mode, reformat the hard drive to hfs and restore from a backup

 

[SoYoung]

No. Forget about that. Rolling back to HFS will be a real pain due to the different partition lay-out and containers. I have done that at High Sierra when they had a bug and I already converted it to APFS. It was a dumb thing to do. I had to first restore the full hard disk layout manually, than re-link all the parts in the partition table and then revert back by Time Machine.

If you’re planning to run a beta on your daily driver machine and are dependent of your files, don’t do it. All my important files are backupped on a Synology (raw files, not just a Time Machine backup) and so I dared to do it.

I have no regrets, it works fine and faster, but it’s up to you to take the gamble. After all, it’s still a very first beta.

Thanks for all the info. I don't want to install the beta version, I just hope the final version will give me the choice if I want to convert my drive or not. I have no problem installing iOS beta's, but I use and need my computer everyday so installing a beta OS never worth it for me. Plus, some apps I use a lot don't work for now on the developper beta.

 

[tazinlwfl]

I have just updated from High Sierra (HFS+) to Mojave, that automatically converts the partition to APFS. I have a 2TB Fusion Drive. It took me around an hour of waiting time. Then everything booted nicely and none of my documents are gone. Everything is where it should be.

So it seems upgrading to Mojave with a Fusion Drive will work from now on!

Okay, I’ve been trying to upgrade to Mojave for the last two days. I have a 3TB fusion drive. First I was coming from straight from 10.12 and that didn’t work (StorageKot error 118). Ended up having to “Reinstall macOS” from Internet recovery which put me on 10.13. Still had HSF+ though, according to Disk Utility. Tried the beta install again, and it failed the same way (StorageKit error 118).
Since I was on 10.13 at this point, the recovery mode allowed me to unmount the drive and try to manually convert the fusion drive to APFS, which failed.

Now I’m stuck in a boot loop that never completes the installation. Sometimes it dumps me into the recovery mode. Hopefully I can get back into a stable 10.13 but 10.14 seems out of reach...

 

[matreya]

I have converted my external HDDs to APFS and there are no issues with any of them.

That is a very courageous thing to do, given that I've discovered Disk Utility cannot repair APFS volumes properly....

I had a 10TB hard drive that was being written to when the power went out, and Disk Utility couldn't repair the volume, I had to reformat it and restore it from a backup.

 

[Clix Pix]

Matreya, your situation vividly illustrates why it is important to have backups of our backups! In the past I have had a couple of external drives fail for one reason or another and so I've always duplicated what is on one to another one for an added measure of safety. Since I have been using external SSDs I have not had any failures (knock on wood!)..... I am also leery of using large-capacity external drives -- largest I ever went with "spinner" external drives was 5 TB.

 

[Fishrrman]

Clix wrote:
"Seems to me that it would make sense then for people to convert their external HDDs and external SSDs to APFS also, in order to have consistency with the computer's internal drive. I have converted my external HDDs to APFS and there are no issues with any of them."

That's very nice, but... what if you want to use one of those external drives with A DIFFERENT Mac that doesn't have High Sierra or Mojave on it?

If it's a Mac with an HFS+ drive/OS, the disks will be unreadable.

 

[Clix Pix]

I am aware of that -- all of my Macs are configured with High Sierra and APFS, and when the time comes, will shift to Mojave. My APFS external drives will remain consistent with them. I am retired and not in the workplace, so I don't usually have any reason to be using one of my external drives with someone else's machine, but that IS a good point. That said, I do have a couple of 64 GB and 128 GB thumb drives which are configured in HFS+ and which will remain so for just that reason. It is unlikely but always possible that I might have a folder or file or two that I want to share with a friend, so I am prepared for that, too.

 

[phuocsandiego]

A word of warning to folks with iMacs and Fusion Drive. Mojave will slow your system! I have a late 2014 iMac Retina 5K with Fusion drive. Booting up was much longer when it was literally seconds in High Sierra. Opening apps is twice as long. I spent 45 minutes on the phone with Apple support and they say they are aware of these issues. We did a remote Internet downgrade back to High Sierra and everything is snappy and speedy as I'm used to.

So while Mojave is compatible with systems with Fusion Drives, it runs about twice as slow after the "upgrade" so I wouldn't recommend it at all. The only thing I found useful in Mojave was the dark mode. That's it. Everything else I'm happy to live without.

 

[DotCom2]

A word of warning to folks with iMacs and Fusion Drive. Mojave will slow your system! I have a late 2014 iMac Retina 5K with Fusion drive. Booting up was much longer when it was literally seconds in High Sierra. Opening apps is twice as long. I spent 45 minutes on the phone with Apple support and they say they are aware of these issues. We did a remote Internet downgrade back to High Sierra and everything is snappy and speedy as I'm used to.

So while Mojave is compatible with systems with Fusion Drives, it runs about twice as slow after the "upgrade" so I wouldn't recommend it at all. The only thing I found useful in Mojave was the dark mode. That's it. Everything else I'm happy to live without.

Thank you very much for posting this. I have the same setup as you. Will pass on Mojave.

 

[ProTruckDriver]

A word of warning to folks with iMacs and Fusion Drive. Mojave will slow your system! I have a late 2014 iMac Retina 5K with Fusion drive. Booting up was much longer when it was literally seconds in High Sierra. Opening apps is twice as long. I spent 45 minutes on the phone with Apple support and they say they are aware of these issues. We did a remote Internet downgrade back to High Sierra and everything is snappy and speedy as I'm used to.

So while Mojave is compatible with systems with Fusion Drives, it runs about twice as slow after the "upgrade" so I wouldn't recommend it at all. The only thing I found useful in Mojave was the dark mode. That's it. Everything else I'm happy to live without.

I'm running Mojave on my Late 2015 Mac with Fusion Drive and I don't see any slow downs. It's running pretty snappy.

 

[EugW]

This is the problem with Fusion drives. Fusion drives in ideal scenarios can be decent performers. But if the scenario changes and is no longer decent, it can slow the system right down.

Slowdowns can also occur in non-ideal situations with SSDs but the negative effect is much milder.

 

[jazz1]

This is the problem with Fusion drives. Fusion drives in ideal scenarios can be decent performers. But if the scenario changes and is no longer decent, it can slow the system right down.

Slowdowns can also occur in non-ideal situations with SSDs but the negative effect is much milder.

Can you describe the conditions in which the slowdowns occur?

 

[dirt farmer]

A word of warning to folks with iMacs and Fusion Drive. Mojave will slow your system! I have a late 2014 iMac Retina 5K with Fusion drive.

So, a word of warning to folks with late 2014 iMac's, then... My iMac works just fine.