Fusion Drive Failed: Go dual SSD, larger Fusion Drive or something else?

Hexley

macrumors 6502a
Original poster
Jun 10, 2009
822
21
After 4+ years the 1TB HDD of the Fusion Drive of my 2012 27-inch iMac has failed.
I knew my HDD was damaged as it clicks like mad and before I split the Fusion Drive I kept getting a Spinning Wait Cursor.

When I split the logical drive into separate SSD and HDD I was able to install macOS on the SSD while the HD

My working budget is restricted to $500

Option 1

- Replace Fusion Drive’s SSD & HDD with two 525GB Crucial MX300 with 3 year warranty
- Reads and writes of 1,000MB/s respectively
- Faster boot times and faster access to apps and data
- Same storage size as my 1TB Fusion Drive but its really fast.
- Chances of fan noise reduced to nil

Option 2

- Keep the original Fusion Drive’s 128GB SSD and replace broken HDD with a 10TB Seagate HDD with 5 year warranty for a 10TB Fusion Drive
- Reads & writes of between 250-400MB/s
- 10TB Fusion Drive will be slightly faster than the original 1TB Fusion Drive with 10x more storage space.

Option 3

- Do not open the iMac and keep the built-in 128GB SSD & buy an external HDD with Thunderbolt 2 or USB 3.
- No more need to open things up and risk of damage.
- Chance of fan noise reduced to nil

I mostly use my iMac to edit 50MP images.

If you were in my place which would you do?
 

petsk

macrumors 6502
Oct 13, 2009
349
217
Number one is not possible. The iMac has a custom blade ssd.
 

nambuccaheadsau

macrumors 68000
Oct 19, 2007
1,742
409
Nambucca Heads Australia
For mine I would go with Option # 3. They are quite difficult these iMacs with the adhesive strip. Easy to smash the glued screen. A mate of mine is a large reseller in Sydney, Australia, and Nick does not allow his techs to crack them because of the number of screens broken.

Packs 'em up and delivers to Apple for them to work on.
 

Fishrrman

macrumors P6
Feb 20, 2009
17,215
5,558
I vote for option 3.
Fastest, easiest, safest, perhaps cheapest.

Run the internal 128gb flash as a standalone boot drive.
Let the failed 1gb HDD be. Just "leave it there", broken.
Add an external USB3 drive of your choosing.

The internal flash drive will run FASTER for you, now that it's "freed from fusion".
The external USB3 drive will be "fast enough for storage".
 

maflynn

Moderator
Staff member
May 3, 2009
63,860
30,384
Boston
I like the simplicity of option 3 as it doesn't require cracking open the iMac.
 

WilliamG

macrumors G3
Mar 29, 2008
8,990
2,401
Seattle
I opened up one of these iMacs last week to replace a broken spinning disk in there with an SSD. It was so easy. You'd quite frankly have to be a muppet to crack the display.

As long as you have the pizza cutter and correct tools, it's super easy. Miles easier than the older Macs where you were fighting dust.
 

mpe

macrumors 6502
Sep 3, 2010
314
184
I like the idea of big fusion drive.

In fact I am in the process of building monster fusion too. I plan to fuse 512GB SSD blade with 8TB SATA internal drive.

On the other hand I wouldn't be considering fusing two SSD drives. This is not optimal configuration. FD works best when combining SSD and HDD. If you plan to use two SSD drives it is better to RAID them (if same size) or keep them separate.
 
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Hexley

macrumors 6502a
Original poster
Jun 10, 2009
822
21
I like the idea of big fusion drive.

In fact I am in the process of building monster fusion too. I plan to fuse 512GB SSD blade with 8TB SATA internal drive.

On the other hand I wouldn't be considering fusing two SSD drives. This is not optimal configuration. FD works best when combining SSD and HDD. If you plan to use two SSD drives it is better to RAID them (if same size) or keep them separate.
My mistake. Was planning to RAID 0 two SSDs.

Would've been awesome if the SSD blade was a 960 Pro. 1TB SSD and 10TB HDD
 

danielwsmithee

macrumors 65816
Mar 12, 2005
1,117
397
I'd do option 4:

Replace the 1TB HD with a 2TB Sata SSD (mx300).

Then create a fusion drive between the blade SSD and the SATA SSD. 2.1 TB of if very fast data.

Just throwing that out there...I can't go back to spinning disks...
 

steve23094

macrumors 68030
Apr 23, 2013
2,626
1,333
I'd do option 4:

Replace the 1TB HD with a 2TB Sata SSD (mx300).

Then create a fusion drive between the blade SSD and the SATA SSD. 2.1 TB of if very fast data.

Just throwing that out there...I can't go back to spinning disks...
I think the general consensus is that you can't fuse two SSDs. There is a good thread on here which I can't find.
 

danielwsmithee

macrumors 65816
Mar 12, 2005
1,117
397
I stand corrected then. That's why I italicised think.

Although I wonder about the general wisdom of such a move anyway. If I wanted one drive I would just create a JBOD array.
The only real difference is that the Fusion will use the faster blade for most accessed files. My guess is you would only see a small increase in performance from ~500MB/s to maybe ~600MB/s. As far as fault tolerance there would be no difference between a JBOD and a Fusion.
 

steve23094

macrumors 68030
Apr 23, 2013
2,626
1,333
As far as fault tolerance there would be no difference between a JBOD and a Fusion.
Slightly worse fault tolerance on a Fusion I think. A single file can be split across both drives. You might be able to recover better from a JBOD failure. Not that I have any experience in either.
 
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danielwsmithee

macrumors 65816
Mar 12, 2005
1,117
397
Slightly worse fault tolerance on a Fusion I think. A single file can be split across both drives. You might be able to recover better from a JBOD failure. Not that I have any experience in either.
That is probably true if you consider going down the recovery option. I just plan for that not being an option.
 

patte

macrumors newbie
Sep 22, 2009
19
0
2 SSD's. Fast and way easier to do backups for. If you need additional storage get a NAS or some cloud storage.