How do you backup a crippled iMac with fusion dive?

[komatsu]

I have an iMac 27" here with fusion drive

System crippled.

Takes 10 minutes to boot. 10 minutes to open Safari. Needless to say TM does not work on it.

How do I back this system up?

 

[mdgm]

Which model do you have?

What capacity is the fusion drive?

Which version of Mac OS?

It would have been best to have tried to do a backup before running into problems.

Do you have another Mac?

Do you have an external drive?

 

[komatsu]

Which model do you have?

A1419

What capacity is the fusion drive?

2000GB + 128GB

Which version of Mac OS?

Catalina latest

It would have been best to have tried to do a backup before running into problems.

I know. Not my system.

Do you have another Mac?

yes.

Do you have an external drive?

yes.


Hope you can suggest something !

 

[Fishrrman]

Get it booted (though it may run slowly).

Get either CarbonCopyCloner or SuperDuper (both are FREE to download and use for 30 days).

Get an external drive.

Now, use either CCC or SD to try to clone the contents of the fusion drive to the backup.

It -might- work...

 

[komatsu]

Thank FM.

system too slow to even download CCC.

Any other suggestions?

 

[Fishrrman]

Can you boot to internet recovery?
command OPTION R

If so, can you open disk utility and do a "first aid" on the fusion drive?

 

[nambuccaheadsau]

What does Disk Utility tell you about free space on the blade drive (128GB PCI-e)? Generally the platter drive fails first and if this in the case you may be able to split the Fusion and clone the blade and then consider replacing the platter with an SSD and re-fusing.

 

[komatsu]

Can you boot to internet recovery?
command OPTION R

If so, can you open disk utility and do a "first aid" on the fusion drive?

Yes, but the progress bar of internet recovery (white screen + spinning globe) gets about 6% across screen and them craps out with an error message.

 

[komatsu]

What does Disk Utility tell you about free space on the blade drive (128GB PCI-e)? Generally the platter drive fails first and if thisnisn the case you may be able to split the Fusion and clone the blade and then consider rewplacing the platter with an SSD and re-fusing.

Thanks nambuccaheadsau but I'm looking for a simpler solution for the time being.

If cloning the 128 PCIe had to be done along with a refusing - I'll do it but there could be a lot of underwater rocks going down that route! Even fusing two blank disks can be problematic sometimes...

 

[easy4lif]

Thank FM.

system too slow to even download CCC.

Any other suggestions?

Can u download ccc from another Mac and use a usb drive to transfer it to the Mac?

 

[easy4lif]

I’d recommend pulling your most important data first with a thumb drive and hoping ccc can pull the rest.

 

[Fishrrman]

OP:

The LAST THING you want to do (if you put an SSD into it) is to "re-fuse" the two drives.

Just "let each drive be ITS OWN drive". This is simpler and less chance of problems afterwards.

I'm guessing that the platter-based drive is failing, and interfering with the bootup process somehow.

There's another thing you could try.
You said you have ANOTHER Mac, right...?
Which Mac, what year made, what OS is on it...?

What might be do-able:
- Get an external drive
- Use your WORKING MAC to install a copy of the OS onto the external drive
- Now, boot from the external drive (use the WORKING Mac first), and create a basic administrative account (just username and password).
- Take this drive to the problem iMac and see if you can boot it to the finder.

The idea here is that even with a problem internal drive, the iMac -might- be able to boot to the finder from an EXTERNAL bootable drive.

Other than this, perhaps the only way you're gonna get the iMac bootable again is to open it, replace the HDD, and try things that way.

 

[komatsu]

OP:

The LAST THING you want to do (if you put an SSD into it) is to "re-fuse" the two drives.

Just "let each drive be ITS OWN drive". This is simpler and less chance of problems afterwards.

I'm guessing that the platter-based drive is failing, and interfering with the bootup process somehow.

There's another thing you could try.
You said you have ANOTHER Mac, right...?
Which Mac, what year made, what OS is on it...?

What might be do-able:
- Get an external drive
- Use your WORKING MAC to install a copy of the OS onto the external drive
- Now, boot from the external drive (use the WORKING Mac first), and create a basic administrative account (just username and password).
- Take this drive to the problem iMac and see if you can boot it to the finder.

The idea here is that even with a problem internal drive, the iMac -might- be able to boot to the finder from an EXTERNAL bootable drive.

Other than this, perhaps the only way you're gonna get the iMac bootable again is to open it, replace the HDD, and try things that way.

FM, thanks for your comprehensive answer.

I have an MBA here and used that to create a bootable external SSD which I booting the problematic iMac up with.

Happy days...Disk Utility saw the fusion drive as one complete volume. So, I quickly went to download CCC. This installed fine on external HDD. Copy process started fine for and lasted 10 minutes than the fusion drive went off the radar. CCC could not recognise any more! The disk will have to be extracted - I can't see any other viable exit strategy. HDD obviously in very bad shape. Even copying to USB thumb drive as suggested by easy4lif, is impossible because of system slowness/paralysis.

>>The LAST THING you want to do (if you put an SSD into it) is to "re-fuse" the two drives.

The last time I setup Catalina with two disks "un-fused" did not work well. System was up and running for 5 days, until it threw up a question mark with flashing hdd icon! iMacs with built- in SSD seem to be primed for this SSD to be the boot drive. When you contravene this, macOS seems to fall over. That is my experience - so I'm very wary of setting up two disks as standalone volumes

 

[Fishrrman]

"System was up and running for 5 days, until it threw up a question mark with flashing hdd icon! iMacs with built- in SSD seem to be primed for this SSD to be the boot drive. When you contravene this, macOS seems to fall over."

Again, I would advise you NOT to "refuse" the drives once you have the new one in there.

Your "?" icon may have indicated something else...

 

[komatsu]

This is finally finished.

Decided to follow FM's advice and not re-fuse. System now up and running.

I have clone of SSD part + old HDD - Not hopeful of recovery though as old HDD behaviour very erratic and I hate working on Seagate disks!

Thanks everyone for the great advice!