Apple changes language about adding an external disk to Fusion Drive

Bierboy said:

Apple has now changed its answer to the question "Can external USB, FireWire, or Thunderbolt hard drives be added to Fusion Drive?" found here.

The answer is now this --
"An external drive cannot be used as part of a Fusion Drive volume. Fusion Drive is designed to work with an internal hard disk drive and internal flash storage."

That seems to confirm what I was told at an Apple Store last week...that you can add an external drive to a Mini using a Fusion Drive...it just can't house the OS. Previously, the answer was very ambiguous...stating simply that you "could not use and external drive with a Fusion Drive." The key change there is Apple stating it cannot be used as part of the Fusion Drive volume.

Click to expand...

I wonder if that is because of the external interface (TB, firewire, USB)? Possibly Fusion only works with SATA bus drives, which are internal in all Mac computers at this time (no oem eSATA ports). I am thinking that Disk Utility may be used to create the Fusion array similar to how it creates RAID arrays, and I don't think those allow external drives to be part of the array either.


-howard

hfg said:

I wonder if that is because of the external interface (TB, firewire, USB)? Possibly Fusion only works with SATA bus drives, which are internal in all Mac computers at this time (no oem eSATA ports). I am thinking that Disk Utility may be used to create the Fusion array similar to how it creates RAID arrays, and I don't think those allow external drives to be part of the array either.

Click to expand...

I have 3 RAID arrays, all external.

Heck, just for fun, 1 array is made of USB disks.

So, no, having external drives isn't a problem with RAID, and I'm hoping it won't be with Fusion drive either.

smithrh said:

I have 3 RAID arrays, all external.

Heck, just for fun, 1 array is made of USB disks.

So, no, having external drives isn't a problem with RAID, and I'm hoping it won't be with Fusion drive either.

Click to expand...

Were those RAID arrays created with Disk Utility using separate interfaces?

If so, then that blows that idea!

I would like a large internal SSD and also use a larger external Hard Disk and then, if Fusion seems to be working well, run that as a Fusion Array. I am really hoping that Fusion functionality will be part of Disk Utility so the user can configure it themselves.

Hopefully, someone will actually receive a Fusion equipped machine in the next day or so and can tell us what is actually going on inside them.

Disk Utility shows a single volume for the Fusion Drive, not the SSD and the HD. When highlighting the first Macintosh HD in the list, it shows Type: Logical Volume Group.



When highlighting the second Macintosh HD in the list, it shows this:



Using iStat Menu's Disk Activity, it shows that there are two separate disks:

It does "work" with external drives, someone's even done it:
http://arstechnica.com/apple/2012/10/more-on-fusion-drive-how-it-works-and-how-to-roll-your-own/

Unsurprisingly, though, that's not a supported option. This reminds me of the "Airport Extreme + USB Hard Drive != Time Machine volume" statement.

Thanks for posting that.

But darn ... looks like Apple didn't give us an easy way to manage the Fusion array with Disk Utility (at least for now) without dropping down into Unix with Terminal. No easy way to disable the functionality and treat it as 2 separate disks, and no easy way to create (or re-create) it if desired.

I suppose that the "About This Mac / System Report" also shows the 2 separate drives?

hfg said:

I suppose that the "About This Mac / System Report" also shows the 2 separate drives?

Click to expand...

Yes!