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fiatlux
Mar 11, 2013, 10:04 AM
I currently have an SSD boot drive and a RAID 0 array of 2x1TB HDDs for data in my Mac Pro (plus a separate 2TB HDD for Time Machine).

The SSD is getting a bit small (80GB Intel X25-m!) now that I put my Lightroom catalog on it.

I was wondering about fusing the SSD and the RAID 0 array in a home-made fusion drive. Would that work?



fiatlux
Mar 26, 2013, 03:23 AM
Nobody?

I see that the question had already been asked but no answer either: http://forums.macrumors.com/showthread.php?t=1480758

benwiggy
Mar 26, 2013, 07:53 AM
Doubtful.
Have a look at the technique for making your own Fusion drive. You should be able to see whether the technique can be adapted to merge three drives into one Logical volume, or not.

fiatlux
Mar 26, 2013, 01:46 PM
I read a bit more about fusion drives and am even more confused...

CoreStorage was introduced in OSX 10.7 but it is unclear whether that includes the "Fusion" logic that would, I guess, relocate frequently accessed files on the faster SSD.

Reading http://macperformanceguide.com/fusion-speed.html it is unclear whether Fusion Drive works at all....

benwiggy
Mar 26, 2013, 02:05 PM
They definitely work. I am WELL into the HDD in terms of capacity, and I use a considerable portion of that on a regular basis. I don't notice any slow downs when the FD might be accessing the HDD bit. Generally, everything acts as if it's at SSD speeds.

Maybe I'm fooling myself, and the blocks that I mostly use are able to fit on the SSD.
Maybe the whole thing is running at slightly less than the speed of the unfused SSD.

I don't know, and frankly, I don't care. As far as I can tell, I've got a 1TB SSD.

fiatlux
Mar 26, 2013, 04:54 PM
Ok, it seems you can put a RAID array in a CoreStorage logical volume:

http://joshkerr.com/encrypting-apple-raid-volumes-in-10-8-mountain-lion/