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Anyone ever realize your fusion drive, isn't?

blackxacto

blackxacto

macrumors 65816
Original poster
Jun 15, 2009
1,288
158
Middle TN
Since I purchased my 17,1 iMac, when running Disk Utility, First Aid, I have never seen the icon for the fusion drive, in any view. There were my external drives and an osx image icon. The iMac seemed to run fine. I just could never repair the fusion drive in any recovery mode, because it never showed in First Aid or in recovery mode. As long as the iMac ran, I didn't care. I took the iMac to the Apple Store to have the screen replaced. Additionally I asked them to wipe the drive and reinstall High Sierra. They did, but just as before, the fusion drive never showed in recovery mode, nor in First Aid. After some calls to Apple Tech, I discovered that the fusion drive has always been split. Even following the trip to the Apple Store techs.

The only way to have an actual fusion drive to show in recovery or first aid is to actually FUSE the main HD w the SSD (creating a virtual main HD). My machine never was. It is now. But you must have backups as the drives will be wiped. Apparently I have been running from the HD alone with no help from the SSD.

https://support.apple.com/en-us/HT207584
 
blackxacto said:
Since I purchased my 17,1 iMac, when running Disk Utility, First Aid, I have never seen the icon for the fusion drive, in any view. There were my external drives and an osx image icon. The iMac seemed to run fine. I just could never repair the fusion drive in any recovery mode, because it never showed in First Aid or in recovery mode. As long as the iMac ran, I didn't care. I took the iMac to the Apple Store to have the screen replaced. Additionally I asked them to wipe the drive and reinstall High Sierra. They did, but just as before, the fusion drive never showed in recovery mode, nor in First Aid. After some calls to Apple Tech, I discovered that the fusion drive has always been split. Even following the trip to the Apple Store techs.

The only way to have an actual fusion drive to show in recovery or first aid is to actually FUSE the main HD w the SSD (creating a virtual main HD). My machine never was. It is now. But you must have backups as the drives will be wiped. Apparently I have been running from the HD alone with no help from the SSD.

https://support.apple.com/en-us/HT207584
Click to expand...

Oh dear. Did you buy your machine directly from Apple as it really would have shipped “fused” that’s the point of the fusion drive obviously. I could imagine an unscrupulous third party stealing he SSD part and selling on the system with HDD only but it seems far fetched...
 
wardie said:
Oh dear. Did you buy your machine directly from Apple as it really would have shipped “fused” that’s the point of the fusion drive obviously. I could imagine an unscrupulous third party stealing he SSD part and selling on the system with HDD only but it seems far fetched...
Click to expand...
Direct from the Apple Store.
 
blackxacto said:
Since I purchased my 17,1 iMac, when running Disk Utility, First Aid, I have never seen the icon for the fusion drive, in any view. There were my external drives and an osx image icon. The iMac seemed to run fine. I just could never repair the fusion drive in any recovery mode, because it never showed in First Aid or in recovery mode. As long as the iMac ran, I didn't care. I took the iMac to the Apple Store to have the screen replaced. Additionally I asked them to wipe the drive and reinstall High Sierra. They did, but just as before, the fusion drive never showed in recovery mode, nor in First Aid. After some calls to Apple Tech, I discovered that the fusion drive has always been split. Even following the trip to the Apple Store techs.

The only way to have an actual fusion drive to show in recovery or first aid is to actually FUSE the main HD w the SSD (creating a virtual main HD). My machine never was. It is now. But you must have backups as the drives will be wiped. Apparently I have been running from the HD alone with no help from the SSD.

https://support.apple.com/en-us/HT207584
Click to expand...

That’s interesting. In the past, disk utility would attempt to “re-fuse” a Fusion drive automatically when run from Recovery or install volume. But I noticed, at least since High Sierra, that it no longer does so, forcing a trip to terminal to prep the drive.
 
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marzer said:
That’s interesting. In the past, disk utility would attempt to “re-fuse” a Fusion drive automatically when run from Recovery or install volume. But I noticed, at least since High Sierra, that it no longer does so, forcing a trip to terminal to prep the drive.
Click to expand...
Yeah... that worked with El Capitan, then not afterwards. No idea why.

OP... command-option-r boot to Internet recovery then use Disk Util to erase both drives. Then follow my instructions here to rebuild the Fusion drive. Once the Fusion drive is back, click restore and attach your backup to bring the OS and everything back in.
 
Weaselboy said:
Yeah... that worked with El Capitan, then not afterwards. No idea why.

OP... command-option-r boot to Internet recovery then use Disk Util to erase both drives. Then follow my instructions here to rebuild the Fusion drive. Once the Fusion drive is back, click restore and attach your backup to bring the OS and everything back in.
Click to expand...

I've already provided in the post the link folks need to actually fuse the two drives. If it is like yours, great.

"In the past, disk utility would attempt to “re-fuse” a Fusion drive automatically"

Apple engineers asked me to use First Aid to repair and refuse the drives together. 1. You must be able to see the two drives in Disk Utility, then, 2. First Aid did not refuse the two drives. I tried it several times. There is only one way to refuse two drives, see the link in the original post.

There has to be a better word than "refuse" :)
 
blackxacto said:
Apple engineers asked me to use First Aid to repair and refuse the drives together. 1. You must be able to see the two drives in Disk Utility, then, 2. First Aid did not refuse the two drives. I tried it several times.
Click to expand...
Like mentioned, that won't work. You will need to do it following those steps in Terminal.
 
Fusion Drives are obsolete according to Apple as they do not support APFS. The closest to a Fusion Drive offering increased performance is a Solid State Hybrid Drive SSHD and available up to 2TB in capacity at a lower cost than SSD
https://www.seagate.com/gb/en/solutions/solid-state-hybrid/

If you are confident enough it is possible to replace the Fusion Drive with an SSHD on your Late 2015 27" 5k iMac by following the iFixit tutorial where you can also purchase the necessary tools
https://www.ifixit.com/Guide/iMac+Intel+27-Inch+Retina+5K+Display+Hard+Drive+Replacement/30522

I have installed Solid State Hybrid Drives in both my Mid 2011 21.5" iMac and Late 2015 21.5" 4k iMac and can thoroughly recommend them.
 
Guy Clark said:
Fusion Drives are obsolete according to Apple as they do not support APFS. The closest to a Fusion Drive offering increased performance is a Solid State Hybrid Drive SSHD and available up to 2TB in capacity at a lower cost than SSD
https://www.seagate.com/gb/en/solutions/solid-state-hybrid/

If you are confident enough it is possible to replace the Fusion Drive with an SSHD on your Late 2015 27" 5k iMac by following the iFixit tutorial where you can also purchase the necessary tools
https://www.ifixit.com/Guide/iMac+Intel+27-Inch+Retina+5K+Display+Hard+Drive+Replacement/30522

I have installed Solid State Hybrid Drives in both my Mid 2011 21.5" iMac and Late 2015 21.5" 4k iMac and can thoroughly recommend them.
Click to expand...

No thanks. I tested many of those. They come no where close to the performance of a Fusion Drive. It uses a caching algorithm instead of data tiering. And if the OS doesn’t optimize the caching (which macOS doesn’t, it’s even less of an improvement). Don’t take my word, just look at the numerous reviews on sites like Anatech and Tom’s Guide.
 
marzer said:
No thanks. I tested many of those. They come no where close to the performance of a Fusion Drive. It uses a caching algorithm instead of data tiering. And if the OS doesn’t optimize the caching (which macOS doesn’t, it’s even less of an improvement). Don’t take my word, just look at the numerous reviews on sites like Anatech and Tom’s Guide.
Click to expand...
I am only going by personal experience. Performance increase is not instantly noticeable until the Hybrid Drive 'learns' which software the user runs on a regular basis then performance does increase dramatically. Although it is good practice to consult reviews and such I rarely take them to be set in stone.
My Late 2015 21.5" 4k iMac came with a stock 1TB 5400rpm HDD which was painful to say the least. Since replacing it with a Hybrid Drive it is a whole different machine so it would suggest macOS handles Hybrid Drives without issue. This is no fluke as I have successfully deployed a Hybrid Drive in my Mid 2011 21.5" as well with equally good results.
 
If the OP's Mac is a 1tb fusion drive iMac, I would attempt to re-fuse the drives (due to the small size of the flash portion of the fusion drive).

However, if it's a 2tb fusion drive model, I'd just leave the drives "separated" (non-fused), as "standalone" drives.

The SSD portion of the 2tb fusion drive is 128gb -- large enough to function very effectively as the boot drive with apps and [basic] accounts.

In fact, the 128 SSD drive will run (and keep running) much faster and better "as a standalone SSD" than it will as the head end of a fusion drive. Keep it lean and clean, and store large libraries of movies, music and pics on the HDD internal drive, as they don't require raw speed.

Of course, one will have two drive icons (and volumes) to manage, but that's trivial -- child's play. I scratch my head when I see Mac users going into a tizzy because they might have to keep files on more than one drive... ;)
 
Last edited:
Fishrrman said:
If the OP's Mac is a 1tb fusion drive iMac, I would attempt to re-fuse the drives (due to the small size of the flash portion of the fusion drive).

However, if it's a 2tb fusion drive model, I'd just leave the drives "separated" (non-fused), as "standalone" drives.

The SSD portion of the 2tb fusion drive is 128gb -- large enough to function very effectively as the boot drive with apps and [basic] accounts.

In fact, the 128 SSD drive will run (and keep running) much faster and better "as a standalone SSD" than it will as the head end of a fusion drive. Keep it lean and clean, and store large libraries of movies, music and pics on the HDD internal drive, as they don't require raw speed.

Of course, one will have two drive icons (and volumes) to manage, but that's trivial -- child's play. I scratch my head when I see Mac users going into a tizzy because they might have to keep files on more than one drive... ;)
Click to expand...

+1, SSD for the OS and frequent applications. And Hard Drive for movies, music or large games. Faster, simpler and better.
 
2TB+128GB Fusion Update: after following the re-fuse steps from Apple, I lost the fusion drive again this week. Late this week, I did not see the fusion in recovery mode, nor in disk utility. But I am now suspecting that I am causing this situation by booting from an external drive and running iDefrag. I have stopped using this app, even though our hard drives are a fragmented mess after heavy use. Yeah, I know I know all the crap, but iDefrag actually smooths out any hard drive data. But I won't be using it anymore if it breaks the fusion drive that takes several hours to recover (I have to start from El Captain on my 17,1 iMac). Anyway, this may be the answer to my situation. I'll know in a few days.
 
I’ve spent a couple of days now w the newly fused Fusion drive, 2tb+128gb. When booted into the fusion drive, I can see the fusion drive in disk utility window, HOWEVER, booting into recovery mode, Apple+R or +Opt+R, there is no fusion drive, only my external drives, and an OSX Base System icon. No fusion drive.

I don’t understand why I am not seeing the fusion drive in recovery modes? I’m not using iDefrag any longer. Aren’t I supposed to see all bootable drives in recovery mode?
 
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Like so many things from pipeline timmy the FD is a short gap cheapo solution , mine was a total disaster

Instead of upping SSD purchasing and lowering the price they foist this unreliable tech on us mugs

Bit worrying that in just a couple of years the os doesn't even support the things - doesn't bode well for the future
[doublepost=1526368269][/doublepost]A trip to terminal to sort out an hd problem.. jeez

I bought a mac for ease of use , having to type stuff into terminal isn't my idea of ease of use

smh ( sounds like I'm trolling - i'm not , i'm just bewildered at the state of the macos these days )
 
Purchased Disk Warrior 5.1, ran it on all my drives (not APFS). Booted into recovery mode using Apple+R, saw my fusion drives. Booted in Apple+Option+R mode, and do not see any fusion drive.

Rebooted following DW repairs. The iMac seems to run smoother. But still no solution as to why I cannot see my fusion drive in recovery mode.
 
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Only solution I am aware of was to do a clean install of the fusion drive and NO MIGRATION. I did drag over my documents folder, and a few plist and cache files, like the TextEdit plist that contains self created styles. Afterwards, when booting from external drives, I now see the fusion drive.
 
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From the DW info, they are working on getting compatible w APSF. DW found nothing major wrong with anything, however, it did clear up minor file discrepancies like wrong flags on files. I'm not a programer so I can't explain what changes w flags. I have used DW in the long past to correct a disk where nothing else worked. But doing a clean install, negates much of its use. Having complete bootable backups is the best insurance. Since 90% of my apps come from the Apple Store, its fast to download & install them all. I have now learned that migration works most times, but nothing replaces the need for a clean (no migration+documents folder drug back, with some plist and pref files) install to get things running as designed.
 
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