You can make a difference in the Apple Support Community!

When you sign up with your Apple Account, you can provide valuable feedback to other community members by upvoting helpful replies and User Tips.

Looks like no one’s replied in a while. To start the conversation again, simply ask a new question.

Fusion drive question

Here's an interesting one! As my 2014 27" core i7 Retina iMac is a bit laggy, I was thinking about replacing its 1TB HDD with an SSD when I remembered that it was originally specified with a Fusion drive. Looking at 'storage', however, I see that it has a 1TB SATA HDD installed. No suggestion of a Fusion set up.But digging deeper in 'system report' I find that it does indeed have a SSD fitted at address disk0s2 although disk utility (see lower picture) indicates that it's not mounted.

Here's the 'storage' information from the system report, which doesn't list the SSD at all.

So, I'm wondering if my system is operational with a Fusion drive or the fusion has become 'unfused' at some point with the SSD lying dormant and the Mac running off the HDD alone? Apart from the lag performance, how else might I test this? I don't have a problem cloning the drive so if it has become 'unfused', could I use Terminal to 're-fuse' it before copying it back? Maybe a new SSD won't be necessary after all.

Posted on Jul 3, 2021 2:06 AM

Reply

Similar questions

9 replies

Jul 4, 2021 1:12 AM in response to Jack-19

Hi jack. Well, I'm pleased to say that after following your suggestion, I now have a working Fusion drive.

As I've not been using this machine for some time, I wonder if I've always been using it in this 'unfused' state, with the SSD sitting redundantly in the background, without realising it. Only two observations; the Time Machine back-up and restore (particularly the restore) took a very long time. The iMac is now noticeably faster. There's no longer any need for me to prise off its screen and change the Fusion to a full SSD after all. Thanks again!

Jul 3, 2021 2:43 AM in response to David Miller7

It appears the system is running entirely from the HDD.


First, make sure you have an up-to-date Time Machine backup, since we are working with internal drives.


Now, as a test, select the "APPLE SSD SD0128F MEDIA", click "Erase", pick a name, and use APFS and GUID. See if you can store data on it by dragging and dropping content to it.


-Jack

Fusion drive question

Welcome to Apple Support Community
A forum where Apple customers help each other with their products. Get started with your Apple Account.