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DIY Fusion drive
- Thread starter Harvdog
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The flashing ? folder means that the computer can't find the boot drive at first, maybe it is caused by the fact that your primary drive in fusion volume is an external one. Verify if your fusion drive is selected in system preferences -> boot drive, if not, select it.
May I impose upon you again? This time I would like to fix the flashing ? w/folder as well as the Firmware password that shows up on each reboot/startup. Can these aberrations be corrected with Terminal or have I corrupted the software beyond hope.
Also . . . . is it possible to upgrade to a 1TB SSD external drive (replacing my 256GB external) without redoing this Create a Fusion Drive litany?
Finally. . . . the change in my iMac which I use primarily with Lightroom and Photoshop is breathtaking. Thanks again for your help and patience.
Harvey
PS my son lives in Denmark and visits Lisbon and Portugal often. My wife(she is of Portuguese decent) and I plan to visit next summer.
I know this thread has grown a bit old by now, but if you still want help with your last points, I think I can take over. I know my way around file systems, partitioning tables and the like.
The flashing ? folder, as Lois mentioned, means the Mac can't find the boot drive. As the external drive is the main, it holds the APFS pre-boot data needed to boot the Mac. If the Mac tries to load this data before the drive is ready to retrieve instructions, seeing as it is an external drive, macOS will think the boot drive is missing.
The way the setup worked before may not have made this issue manifest, but it is sort of a hardware issue so it isn't really easy to fix. Only solution is an external drive setup that is quicker to start responding to requests from the system. Holding alt on boot to get the boot picker will also give the drive time to get ready before booting, so it might help avoid it, but it adds an extra step to booting.
Regarding the firmware password, we can fix that. If the disk is FileVault encrypted, you'll need to disable that - This may also help with the flashing ? folder, since the encryption might add latency to the drive, but I don't know if that's the case - There's also the risk it could make it worse if the computer doesn't wait as long before trying to boot the drive without the firmware password prompt, but you can refer to my suggestion above for delaying the computer's request to boot.
Booting into Recovery Mode, in the Utilities menu from the Menu Bar, there's an option for setting Firmware Passwords. You can disable it there too. - Again, FileVault Encryption will turn it on.
Sorry, no. The data on each drive is not just split on a file level or something simple like that. It's split on a block level, so you can't take any piece out of the chain. The two drives are completely dependant on each other when they are fused together. A single file can exist partially on each drive but wholely on neither. Thus, replacing the one drive, will rip that file apart and make it entirely unreadable. - And it doesn't even necessarily get ripped apart in the middle. It could be the first 10% are on the HDD, the next 10% on the SSD, then 30% on the HDD 25% on the SSD and the last 25% on the HDD - or any other split. And that's for every single file there is.
You'd have to create the Fusion all over - though knowing the correct process from the beginning would of course speed it up.
Cheers from Denmark, matey.
The flashing ? folder, as Lois mentioned, means the Mac can't find the boot drive. As the external drive is the main, it holds the APFS pre-boot data needed to boot the Mac. If the Mac tries to load this data before the drive is ready to retrieve instructions, seeing as it is an external drive, macOS will think the boot drive is missing.
The way the setup worked before may not have made this issue manifest, but it is sort of a hardware issue so it isn't really easy to fix. Only solution is an external drive setup that is quicker to start responding to requests from the system. Holding alt on boot to get the boot picker will also give the drive time to get ready before booting, so it might help avoid it, but it adds an extra step to booting.
Regarding the firmware password, we can fix that. If the disk is FileVault encrypted, you'll need to disable that - This may also help with the flashing ? folder, since the encryption might add latency to the drive, but I don't know if that's the case - There's also the risk it could make it worse if the computer doesn't wait as long before trying to boot the drive without the firmware password prompt, but you can refer to my suggestion above for delaying the computer's request to boot.
Booting into Recovery Mode, in the Utilities menu from the Menu Bar, there's an option for setting Firmware Passwords. You can disable it there too. - Again, FileVault Encryption will turn it on.
Sorry, no. The data on each drive is not just split on a file level or something simple like that. It's split on a block level, so you can't take any piece out of the chain. The two drives are completely dependant on each other when they are fused together. A single file can exist partially on each drive but wholely on neither. Thus, replacing the one drive, will rip that file apart and make it entirely unreadable. - And it doesn't even necessarily get ripped apart in the middle. It could be the first 10% are on the HDD, the next 10% on the SSD, then 30% on the HDD 25% on the SSD and the last 25% on the HDD - or any other split. And that's for every single file there is.
You'd have to create the Fusion all over - though knowing the correct process from the beginning would of course speed it up.
Cheers from Denmark, matey.
I really don't get all this hatred against the Fusion Drive. For the vast majority of time I don't notice the difference between it and my all-SSD setups; Including when I run pre-release systems on a TB2 SSD on the same hardware otherwise.
It was a night and day difference. I don’t like things that don’t work and neither of our 2013 imacs were worth a darn with fusion drives.