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Making a fusion drive in my 2011 27" iMac-- possible to enable trim on the SSD?

O

Obioban

macrumors regular
Original poster
Oct 19, 2011
216
254
Aftermarket SSD with normal HD, both on SATA 6 buses. By default Apple doesn't enable trim on aftermarket SSD's, but traditionally I've turned it on using terminal.

Can I do that if fuse it? Or, if I have trim enabled before I fuse it, will it stay enabled?

Thanks!
 
dangerly

dangerly

macrumors regular
Oct 27, 2009
151
5
European Dis-Union
Last year i made a fusion drive in my 2009 24" iMac.
To enable TRIM i downloaded and installed TrimEnabler.
Fusion drive is working perfectly with TRIM enabled on the SSD (Samsung 250 GB).
 
O

Obioban

macrumors regular
Original poster
Oct 19, 2011
216
254
As I remember, there's something wrong about how trim enabler turns on trim, so I was hoping to do it using the terminal-- possible?

And the fusion drive understands trim/will only be trying to enable trim on the SSD portion of it?
 
O

omvs

macrumors 6502
May 15, 2011
495
20
I've been user trim-enabler on multiple fusion setups, though my current one doesn't need it (spare SSD from rMBP). I've always enabled it after installation or time-machine restore.

I'm not sure how TRIM works with a fusion setup - does it even matter? My understanding is the coreStorage migrates large blocks between the drivers based on usage, so it may be large enough trim doesn't matter, or it may be there's basically never any unused space.

However I figure any garbage-collection on the drive won't understand any fusion setup, and since I'm also encrypting I have to assume it can't do any garbage collection -- so maybe TRIM will help, but it certainly won't hurt...


I wouldn't expect the command-line hacking to be any different than using TrimEnabler - you'll probably have to redo every OS update, but it should be sticky.
 
marzer

marzer

macrumors 65816
Nov 14, 2009
1,398
123
Colorado
Obioban said:
As I remember, there's something wrong about how trim enabler turns on trim, so I was hoping to do it using the terminal-- possible?

And the fusion drive understands trim/will only be trying to enable trim on the SSD portion of it?
Click to expand...

No. There's nothing wrong about how Trim Enabler turns on trim. It's one of the most popular ways of enabling TRIM on an aftermarket SSD installations on a Mac. I've used it for years on both do-it-yourself SSD and Fusion Drive installations.

No. The Fusion Drive doesn't understand it at all. TRIM is a function that occurs at a lower level of the operating system inconsequential to whether the drive is configured as part of a Fusion logical volume or not. TRIM can only be enabled on a solid-state drive.
 
marzer

marzer

macrumors 65816
Nov 14, 2009
1,398
123
Colorado
omvs said:
I've been user trim-enabler on multiple fusion setups, though my current one doesn't need it (spare SSD from rMBP). I've always enabled it after installation or time-machine restore.

I'm not sure how TRIM works with a fusion setup - does it even matter? My understanding is the coreStorage migrates large blocks between the drivers based on usage, so it may be large enough trim doesn't matter, or it may be there's basically never any unused space.

However I figure any garbage-collection on the drive won't understand any fusion setup, and since I'm also encrypting I have to assume it can't do any garbage collection -- so maybe TRIM will help, but it certainly won't hurt...


I wouldn't expect the command-line hacking to be any different than using TrimEnabler - you'll probably have to redo every OS update, but it should be sticky.
Click to expand...

As I mentioned above, TRIM occurs at a low level of the OS, garbage collection occurs at the device level inside the drive itself. Neither TRIM or garbage collection are aware of, or impeded by, the logical configuration of the drive such as encryption or Fusion.

And TRIM will always help in the operation of an SSD as it compliments the garbage collection function built into the drive.
 
Weaselboy

Weaselboy

Moderator
Staff member
Jan 23, 2005
34,137
15,601
California
Obioban said:
As I remember, there's something wrong about how trim enabler turns on trim, so I was hoping to do it using the terminal-- possible?
Click to expand...

Not any longer. The V1 of TRIM Enabler was using a Snow Leopard kext file included with the app and just substituting that file for the existing kept file to enable TRIM. This caused problems when Lion and later OS X versions came out, so starting with V2 TRIM Enabler just runs the Terminal commands for you to tweak your existing kext file. So TRIM Enabler and Terminal have the exact same end result now.
 
O

Obioban

macrumors regular
Original poster
Oct 19, 2011
216
254
Weaselboy said:
Not any longer. The V1 of TRIM Enabler was using a Snow Leopard kext file included with the app and just substituting that file for the existing kept file to enable TRIM. This caused problems when Lion and later OS X versions came out, so starting with V2 TRIM Enabler just runs the Terminal commands for you to tweak your existing kext file. So TRIM Enabler and Terminal have the exact same end result now.
Click to expand...

Awesome, good to know and that is exactly what I couldn't quite remember.

Thanks!
 
JPamplin

JPamplin

macrumors 6502
Mar 12, 2009
320
63
Nashville, TN
I'd use a free utility...

http://chameleon.alessandroboschini.it/index.php

Chameleon has a beta version which enables TRIM on third-party SSDs, which I use every time I install, for instance, a Samsung 840 EVO into a Mac (even for Fusion Drives). It works and it's free.

Mind you, the setting may reset with every OS version upgrade. So after 10.9.5, you need to check it, and go back to the site above to see if the app works with it. He's pretty good about being responsive.

And YES, absolutely do a Fusion Drive on your iMac - night and day!

JP
 
SaSaSushi

SaSaSushi

macrumors 601
Aug 8, 2007
4,156
553
Takamatsu, Japan
JPamplin said:
http://chameleon.alessandroboschini.it/index.php

Chameleon has a beta version which enables TRIM on third-party SSDs, which I use every time I install, for instance, a Samsung 840 EVO into a Mac (even for Fusion Drives). It works and it's free.
Click to expand...

Thank you for this heads up. Here I was, ever since upgrading to 10.9.4, running my 840 EVO with no TRIM support and totally ignorant of the fact. I just grabbed the beta version of Chameleon and reenabled it.

Made a mental note to check TRIM status in the future after every OS X update or, better yet, check with Chameleon to see if the update disables it and if there is a new version available.
 
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