Cloning APFS High Sierra

[Guy Clark]

Yes, you can clone an APFS source to a HFS+ destination.

APFS can work on SSHD, just not Fusion Drive. They are completely different.

SSHD is just a normal HDD with a small SSD as cache (duplicated data from the HDD) to store the frequent access data for fast reading. All data is primarily stored on the HDD. And the "cache" is controlled by the hard drive onboard controller. The whole process is totally transparent to the OS.

Fusion Drive is an OS function that allow user to combine ANY two hard drives to form a larger single partition. The OS will automatically determine which hard drive is faster and use it primarily. When the faster hard drive is full, it will leave the frequent accessed data on the faster drive, and move the remaining data on the slower drive. BOTH hard drives will be used to store data, NO data duplication.

In general, a Fusion Drive will consist one SSD and one HDD. However, you can actually combine a PCIe SSD with a SATA SSD etc to from a Fusion Drive. The OS can still automatically use the PCIe SSD as the primary storage. This is an OS function, and not supported by APFS yet.

Many thanks for your help I have successfully cloned the APFS partition to HFS+ using Carbon Copy Cloner and even created a Recovery Partition. I have tested it out running it from a USB 3.0 external enclosure and the performance is massively improved. I am now wondering if I need to open up the iMac at all and just keep it running from USB 3.0
What do you think?
Once again many thanks

 

[h9826790]

Many thanks for your help I have successfully cloned the APFS partition to HFS+ using Carbon Copy Cloner and even created a Recovery Partition. I have tested it out running it from a USB 3.0 external enclosure and the performance is massively improved. I am now wondering if I need to open up the iMac at all and just keep it running from USB 3.0
What do you think?
Once again many thanks

IMO, unless you have at least 95% confidence that you can open up the iMac and won't damage anything. Running the SSD via USB 3.0 connection is good enough for most people. The main disadvantage is just can't use TRIM, which may affect write speed in long run, but virtually won't affect OS performance (mainly determined by 4k random read performance).

No TRIM will also shorten the SSD's life span a bit. But TBH, I still have seen a single SSD that under normal use already run out of life. Usually a PCB fail before the cells die.

I've tried

1) SATA SSD boot from SATA II port
2) SATA SSD boot from SATA III port
3) SATA SSD boot from USB 3.0 port
4) SATA SSD boot from USB 2.0 port

In case 4, the bandwidth limitation is really too large, which can make me easily feel the difference (but still much much faster than running OS from a normal HDD), the rest 3 are feeling identical under most normal daily use.

 

[LarryJoe33]

Just to clarify please. I currently have a 4k iMac with a 5400rpm HDD formatted APFS. Can I successfully clone to a Seagate SSHD formatted HFS+ ?

I intend to upgrade the internal 5400rpm HDD to the SSHD and I am asking this question as I have seen APFS does not work on Hybrid Drives. Is this correct ?

Thank you.

Can I ask why you are not just going straight SSD?

 

[Guy Clark]

IMO, unless you have at least 95% confidence that you can open up the iMac and won't damage anything. Running the SSD via USB 3.0 connection is good enough for most people. The main disadvantage is just can't use TRIM, which may affect write speed in long run, but virtually won't affect OS performance (mainly determined by 4k random read performance).

No TRIM will also shorten the SSD's life span a bit. But TBH, I still have seen a single SSD that under normal use already run out of life. Usually a PCB fail before the cells die.

I've tried

1) SATA SSD boot from SATA II port
2) SATA SSD boot from SATA III port
3) SATA SSD boot from USB 3.0 port
4) SATA SSD boot from USB 2.0 port

In case 4, the bandwidth limitation is really too large, which can make me easily feel the difference (but still much much faster than running OS from a normal HDD), the rest 3 are feeling identical under most normal daily use.

Once again many thanks for your help. I have determined I am more than happy with the performance of the SSHD running macOS High Sierra using USB 3.0 and will not be opening the iMac up. The internal 5400rpm I will use as a clone should the SSHD fail.
What is a mystery however is why Apple would ever sell the iMac with a 5400rpm Hard Drive in the first place. It is was painfully slow.
Thank you anyway I am now more than happy with the performance.
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Can I ask why you are not just going straight SSD?

I am going with SSHD for increased performance and capacity. I have worked with Seagate Hybrid Drives for some time now and have found them to be an excellent compromise. Not quite the speed of SSD but noticeably faster than 7200rpm even when running from a USB 3.0 enclosure.

 

[h9826790]

Once again many thanks for your help. I have determined I am more than happy with the performance of the SSHD running macOS High Sierra using USB 3.0 and will not be opening the iMac up. The internal 5400rpm I will use as a clone should the SSHD fail.
What is a mystery however is why Apple would ever sell the iMac with a 5400rpm Hard Drive in the first place. It is was painfully slow.
Thank you anyway I am now more than happy with the performance.

That sounds perfect to me.

1) SSHD has zero performance / function impact running over USB 3.0. So, no point to take risk and make it internal.

2) Leave the original internal HDD inside as backup boot drive also sounds a good way to use it. I also use CCC to clone my boot drive to an internal HDD daily as backup boot drive. This can assure my Mac has virtually zero down time due to boot drive failure. Also, if I have doubt about any OS update / software. I can alway apply that on the backup drive. Make sure I am happy with that before I apply that to the primary boot drive.

 

[Master Tom]

Carbon Copy Cloner is in Contradiction to its Name, not cloning the Volumes.
It is simply copying Files.

 

[Apple_Robert]

Carbon Copy Cloner is in Contradiction to its Name, not cloning the Volumes.
It is simply copying Files.

You are incorrect. CCC can make a bootable clone of your drive. It does clone the volume of the drive.

 

[Master Tom]

You are incorrect. CCC can make a bootable clone of your drive. It does clone the volume of the drive.

Carbon Copy Cloner does not create a bootable Copy of your Volumes.
It is not cloning the Drive. It is simply copying Files.

 

[ibarnett]

Carbon Copy Cloner does not create a bootable Copy of your Volumes.
It is not cloning the Drive. It is simply copying Files.

Well I wonder then how I recently managed to boot from CCC clone of my working drive????

 

[Fishrrman]

Master Tom wrote:
"Carbon Copy Cloner does not create a bootable Copy of your Volumes.
It is not cloning the Drive. It is simply copying Files."

Fishrrman's credo:
Reality is what it is. It is not what we believe it to be.

Have you ever actually USED (either) CCC or SuperDuper?

 

[Master Tom]

Master Tom wrote:
"Carbon Copy Cloner does not create a bootable Copy of your Volumes.
It is not cloning the Drive. It is simply copying Files."

Fishrrman's credo:
Reality is what it is. It is not what we believe it to be.

Have you ever actually USED (either) CCC or SuperDuper?

I have installed everything from Scratch, because the CCC-Backup does not boot.

 

[Fishrrman]

"I have installed everything from Scratch, because the CCC-Backup does not boot."

Then I'm guessing that -something- went wrong during the cloning process.
It would help if you gave us more information.
Questions:
- is the source volume APFS or HFS+ ?
- is the target volume APFS or HFS+ ?
- are you using the most recent release of CCC ?

- is the target drive USB3, or something else ?
- what is make of the target drive (if you bought it pre-assembled) ?
(there are SOME USB drives that just won't boot a Mac -- a problem that is specific to the drive, not to the fact that it's a CCC clone, or whatever)

Final thought:
Since you had a problem with CCC, why not download SuperDuper and give it a try instead?
The SD download is also free.

 

[MSastre]

I have installed everything from Scratch, because the CCC-Backup does not boot.

Both CarbonCopyCloner and SuperDuper will make bootable clones of AFPS and HFS+ systems. Just because you can't make it work does not mean that everybody else is wrong. People have been happily making/using bootable copies of their drives for years using either program. I've been using SuperDuper for many years. Fishrrman makes some excellent points .... more info needed.

 

[h9826790]

You are incorrect. CCC can make a bootable clone of your drive. It does clone the volume of the drive.

I think that’s really nothing more than files coping. Cloning usually mean identical from bit to bit, no change

I have installed everything from Scratch, because the CCC-Backup does not boot.

CCC backup does boot (if you do use it correctly). I use that few times already. However, I tends to agree that is not clone but just copying files.

IMO, Clone means identical bit to bit in the exact order for the whole partition. CCC is not doing that.

However, CCC manage to copy all files to the backup partition with correct permission etc, and make it bootable.

 

[dsemf]

CCC is doing a logical clone instead of a physical clone. A logical clone is flexible in that the target file system and/or disk space don't have to match the source. The goal in either case is a bootable system.

DS

 

[simonsi]

Carbon Copy Cloner does not create a bootable Copy of your Volumes.
It is not cloning the Drive. It is simply copying Files.

It does by default. If you choose to select only certain files then it warns you if CCC knows it is no longer bootable.

My CCC clones have always booted no problem. That does not mean you didn't have an issue or otherwise render your CCC copy unbootable.