Found this article...is this the same thing?
http://mattgemmell.com/2011/06/21/using-os-x-with-an-ssd-plus-hdd-setup/
Article is below
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Using OS X with an SSD plus HDD setup
JUN 21ST, 2011
Solid-state drives (SSDs) are becoming commonplace, and the first time you use one as a boot drive, you realise why - theyre faster than hard drives to a ridiculous degree. The downside is theyre currently still very expensive compared to hard drives, such that only smaller capacities are currently affordable. Macs are now being offered with what I call mixed drive configurations, including both a (small; often 256 GB) SSD and an HDD, and many people wonder how to make the most of this setup.
I have two SSD-equipped machines here, including a mixed-drive iMac, and have recently configured it in what I believe is a good compromise setup to take advantage of SSD speed without sacrificing the roomy storage of a hard drive (or causing excessive wear to the SSD). This is just one possible setup, but I hope its useful to you.
The basic approach here is to have the OS on the SSD (the default setup on mixed-drive Macs), and to move certain folders onto the hard drive, providing links to those folders in the places they used to be. Before beginning, let me try to pre-empt two possible comments:
You can tell iTunes (etc) to keep its data elsewhere!
Indeed you can (usually by holding the alt/option key whilst launching the app), but youll have to do it for each and every app that has such a capability - and some apps wont let you. The method Im about to describe, however, will just work, without changing any settings.
You can put the home folder on the hard drive, and use the Accounts pane to point to it!
Thats also true (unlock the Accounts pane, then right-click on your account in the list), but youre losing the speed benefit of having certain parts of your home folder on the SSD (such as caches, preferences, your development projects and so forth).
Its your choice if you want to use one of the above limited expedients, but I feel that you can find a better balance by doing just a little bit of extra work.
Copying and Linking folders on the HDD
With that all said, lets offload some folders to the hard drive. Its extremely easy to do, even though theres a tiny, tiny bit of typing on the Terminal involved. If youre scared of that, by all means run away now and get a friend to help. Also, make sure you have an up-to-date backup of your boot drive before beginning; thats just common sense.
Were really just going to be repeating the same process over and over, once for each folder that you want to live on the HDD instead of the SDD. The process is simply this:
In the Finder, copy the folder from the SSD to the HDD. Check that it was copied successfully.
In Terminal, cd to the location of the original folder (on the SSD), and delete it via sudo rm -rf foldername.
In Terminal, still in the location of the original folder you just deleted, make a link to the copy of the folder on the HDD, via ln -s /Volumes/HDDname/path/to/foldername.
(In steps 2 and 3 above, you should of course substitute the actual names and paths of the relevant folders and volume instead of foldername, HDDname, and path/to/foldername. Hopefully thats obvious. For the ln command, think of the syntax as being put a link here, that points to there.)
Thats it. Youll probably want to put all these copied folders somewhere sensible on the HDD; I created a folder called matt at the root of the HDD, and copied my folders into there - you can see a picture of it below. Ive heard that you should not create a Users folder at the root of a non-boot disk, however.
You should also note that, if youve copied and linked one of the special folders in your home directory (such as Pictures), the new folder/link wont have the special icon that the Finder usually provides. Thats normal, and completely harmless. You may also need to re-add the folder to the Finders sidebar.
Theres nothing else to it, except to decide which folders to actually offload.
Choosing which folders to put on the HDD
This is a personal decision, but generally youll want to offload folders that fit any of these criteria:
Are very large. Your SSD is small, and it shouldnt be bursting at the seams.
Will change extremely often, particularly if they contain large files. SSDs are notably subject to wear, especially if they dont support TRIM.
Contain files which arent involved in performance-critical work.
Try to keep in mind that the HDD is perfectly good enough for almost everything, and that weve been using HDDs for years. Its not the poor cousin, and it hasnt suddenly acquired the performance characteristics of a floppy disk drive. This is just about balance, and sensible optimisations to help get the most from the new SSD.
In my own case, I offloaded several of the folders in my home directory onto the HDD, as shown in the screenshot below.
Note that the Dropbox folder is created by the utility of the same name, and that the Backups folder is one I created for my own use.
In addition to those, as shown in the picture, I offloaded Downloads, Movies and Pictures. I dont keep things permanently in my Downloads folder yet its contents change constantly, so it was an excellent candidate for offloading. I also dont heavily use iPhoto or Aperture, and keep my graphic work files in my Documents folder, so I could offload Pictures. I dont do any video editing, and have a large Movies folder, so I offloaded it too.
I did not offload the Music folder, but I did offload the actual media files (and mobile apps) that iTunes uses, as shown in the picture of my Music folders contents below.
Note that on your Mac, the iTunes Music folder may instead be called iTunes Media. The reason I didnt offload the entire Music folder was to keep my GarageBand files on the SSD for performance, and nor did I offload the entire parent iTunes folder so that I could keep iTunes library and metadata files on the SSD for the same reason.
You may find that youll want to keep some of those folders on the SSD, and equally you may find that you want to offload additional folders to the HDD. For example, I also put my Virtual Machines folder on the HDD, and you might also want to put your Steam games there (they live in ~/Library/Application Support/Steam).
Just follow the same process as above, and you should be fine. It takes only a few minutes, and it should ensure that you get the maximum benefit from the SSD without being unduly hindered by its comparatively small capacity.
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