Mac Pro SSD and Hard Drive Combo: How and Why

| Ted Landau's User Friendly View

Ever since I bought a MacBook Air last fall, I have thoroughly enjoyed the quiet and snappy performance of its SSD (solid-state drive). The only “downside” is that my desktop Mac Pro remains my primary workhorse. That’s why, after considerable procrastination and penny-counting, I finally took the plunge. Last weekend, I purchased an SSD for my 2009 Mac Pro.

Was it worth it? You bet. Startup times are now much faster. Applications open with a pop. Everything seems to take less time. And I almost never hear the whirring sound of my (still installed) mechanical hard drives.

However, at several points over the weekend, I was much more uncertain as to exactly how “worth it” my decision would turn out to be. The process of getting everything set up and running smoothly took the better part of two days. Even now, I confront an occasional minor blip in some application. At several points during the process, my anxiety level sky-rocketed as I worried about losing data. While not difficult to do, the task requires a hefty chunk of time and a considerable level of Mac knowledge.

To help decide if an SSD upgrade is right for you, and to assist in making the transition go as smoothly as possible, I offer the following recount of my weekend odyssey:

Purchase the SSD

An essential preliminary step was to buy an SSD. Based on their excellent reputation, I decided to get the drive from Other World Computing (OWC). A key component of this purchase is to decide how large an SSD to buy. All other things being equal, larger is better. If you get a drive large enough to hold all the data currently on your startup drive, the transition should be quite simple — no different than transferring data from one mechanical hard drive to another.

Unfortunately, all other things are not likely to be equal. In my case, to get an SSD large enough to serve as a swap for my current hard drive, I would have needed OWC’s 480GB SSD. It cost over $900. No way was I going to spend that much for a drive upgrade.

There are a couple of solutions to this dilemma. The one I chose (which is the most common) was to get a drive just large enough to hold my Mac OS X System Software and Applications folder. For me, this meant getting OWC’s 115GB Mercury Extreme Pro SSD at the much more affordable price of $230. My Home directory and the rest of my content would remain on my current drive.

I needed to make one more decision before ordering my drive. Because SSD’s are 2.5” and standard drives are 3.5”, the trays that come with the Mac Pro do not directly accommodate an SSD. OWC offers several solutions for this. The one I chose (which I highly recommend) is to get the OWC Mount Pro drive sled. This holds the SSD and replaces one of the empty trays inside the Mac Pro.

SSD drive

Install the SSD

After the SSD and sled arrived, it was relatively simple to install them. Using the screws from an empty Mac Pro drive tray, I attached the SSD to the OWC tray. I then slid the tray into the empty bay. Done.

I started up the Mac Pro and was greeted with a message stating that the newly recognized SSD needed to be initialized. Using the Partition section of Disk Utility, I did so. I was now good to go.

Transfer data to the SSD

The next step was to transfer my existing System Software and Applications folder to the SSD, making sure that the SSD would be a bootable drive.

I wasn’t sure the best way to proceed. As a result, I had a couple of false starts.

My first attempt began with installing Mac OS X from an Apple Install DVD — and then transferring data across drives. It did not work well. I eventually wound up with a Home directory that would no longer function as an admin account.

Neither Apple’s Migration Assistant utility nor SuperDuper (my backup software) were up to the task. They didn’t provide the level of fine tuning I required to transfer only the specific software I wanted.

What finally worked was to start over with an empty SSD and use Carbon Copy Cloner to select and transfer the desired items. Essentially, I copied everything to the SSD except the root level Users, Developer and Documents directories. That’s not 100% true. I copied over the shell of my Home directory within Users. That is, I copied my “landau” folder but not any of the files or subfolders within it. This was one of those instances where my general knowledge of how Mac OS X worked allowed me to sidestep a problem. You’ll see what I mean in a moment.

Start up from the SSD drive

I had now arrived at the first real test of my efforts. I selected the SSD as the startup drive in System Preferences and restarted. Would the Mac Pro boot successfully? Yes. It did so, logging me into my “empty shell” landau account — even recognizing the account’s existing basic data (account name, password, MobileMe user name, etc.).

Change Home directory link

I was far from done with my work for the day. At the moment, the SSD was using the empty shell as a Home directory. I wanted it instead to link to my “real” Home directory, the one that still resided on my prior startup drive.

To do this, you need to go to Accounts System Preferences, unlock the pane (if needed) and control-click on your account name. From the contextual menu, select Advanced Options. Here is where it paid off for me to have already created an empty shell account with the same name. From the sheet that dropped down, I clicked the Choose button to the right of the Home directory listing. I entered the location of my existing “real” Home directory on my prior startup drive.

Note: Don’t worry about the warning in Advanced Options that says: “Changing these settings may damage this account…” Just don’t make any changes besides the one described here.

Once again, I restarted. Success again! The SSD was the boot drive but it was correctly logging me into my old Home directory on my old startup drive. At this point, I could delete the “empty shell” account on the SSD itself.

Advanced Options

Create another admin account

There was one more thing I needed to do before finishing up my initial setup: create a second admin account located on the SSD. Why? In case the link between the SSD and my Home directory got messed up or the Home directory drive went down, I needed to be able to boot from the SSD. To do that, I would need the additional account for login. As a test, I tried to boot from the second account. Success yet again.

I was now done with this stage of the transition. It had taken several hours, there had been a few false starts and a bit of anxiety, but it was over. However, this was only the first part of the process. The second part would take even longer. I decided to call it a day at this point and pick up the task in the morning.

Shift the backups

I maintain multiple types of backups for my startup drive. The main one is a mirror of the entire drive — updated every morning via SuperDuper. With my data now split across two drives, my backup arrangement required some modification.

The first thing I did was add an additional hard drive to serve as a new mirror of the SSD. This went quickly and smoothly.

Next up was to eliminate the System Software and Applications folder from my former startup drive, leaving it with just my Home directory and other content not on the SSD. There were numerous ways I could accomplished this. Here’s the way I decided to go: 

  1. I booted my Mac Pro from the existing mirror of my former startup drive.

  2. Using Disk Utility, I reformatted/erased the former startup drive.

  3. Using Carbon Copy Cloner, I copied just the desired content (e.g., my Home directory) from the mirror to the former startup drive.

  4. The former startup drive (which I will henceforth refer to as my Home directory drive) was now set up as desired. I restarted from the SSD. The SSD still correctly linked to the Home directory drive! Whew!

  5. I next erased the mirror drive. Using SuperDuper, I made a mirror of the Home Directory drive.

As you might imagine, due to the amount of data being transferred across drives, these steps took several hours to accomplish. The task also raised my anxiety level by several notches. Anytime I start erasing critical drives, I am concerned that something may go wrong — and I will wind up with both the original and backup of data deleted. That’s why I breathed a long sigh of relief when this was all over without incident.

There remained one minor issue for which I had no solution. Both the SSD and its mirror link to my Home directory drive. That is, the mirror of the SSD drive does not link to the mirror of the Home directory drive. This means if something should go wrong with the Home directory drive, neither the SSD nor its mirror would startup as normal. Should this occur, the SSD will presumably startup from the alternate admin account I created. At this point, I could establish a link to the Home directory mirror, if needed. I decided this was acceptable — and left it at that.

Clean up

I’d like to tell you that the story of my SSD transition was now over. Unfortunately, such was not the case. What remained were more irritations than major problems, but they still took time to fix. Most of the problems were a consequence of the change I had made to my Home directory path. Here are the main things I needed to adjust:

  • My backup scripts in SuperDuper no longer worked. I had to delete them and recreate new ones.

  • The links between my drives and my Backblaze online backup were broken. I needed to reset them to track the separate SSD startup and Home directory drives.

  • Dropbox could no longer find the local copy of my Dropbox folder. I had to re-establish the link.

  • iTunes had numerous problems locating media files. At one point, iTunes claimed that all the content on my iPhone was “unauthorized” and would be deleted if I proceeded to sync. It took some time to sort of all of this out — but I eventually did so. These issues were almost certainly exacerbated by the fact that, long before the SSD’s arrival, I had moved my iTunes Media content to a separate location (outside of my Home directory). 

Wrap up

Recapping what I said at the top of this article, despite the time and hassles, the transition to an SSD was definitely worth doing. After all, I only had to do the work once. Now that it is behind me, I can reap the benefits with no further hassles. I even see benefits to splitting my setup across two drives. For example, if I ever need to erase my startup drive and reinstall Mac OS X, I can do so without disturbing any of my personal data.

That said, unless you feel confident about and comfortable with performing the tasks described here, “don’t try this at home.” Get someone to help out — and then go for it.

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Wow- this was posted as I literally just completed an SSD installation on my 2008 Mac Pro 8-core (I opted for a 128GB Crucial RealSSD 300, and Icy Dock 2.5 to 3.5” HDD converter from OWC). I definitely recommend it! It’s like having a brand new MUCH zippier machine. Booting is almost instantaneous, and apps such as Photoshop are incredibly speedy.

However, I think that the setup described here might lead to a few problems…. I think that setting things up BEFORE installing the new drive would work much better:

(1) Use Carbon Copy Cloner to copy the entire ‘Users’ folder to a new empty HD (I used a new 1TB drive)

(2) Once the copying is complete, rename the original ‘Users’ folder to something else (e.g. ‘Users-old’) In the Terminal:

sudo mv Users Users-old 

(3) Create a symlink to your newly copied Users folder on the new drive:

sudo ln -/Volumes/[i]NEWDRIVE[/i]/Users /Users 

(4) Restart the computer.

(5) Once you have verified that the symlink works, DELETE the ‘Users-old’ folder on the original disk. This will leave Applications and system files on one disk, and Users on the other disk. The reason for doing it this way rather than the way described in the article is that any subsequent users would be created in the still-existing Users folder on the original disk, and would also require re-linking… This way, no re-linking is needed - THe system sees the Users folder as if it were on the same drive.

(6) Clean up the Applications folder and remove or move any unnecessary files to free up space.

(7) Install the new SSD, reformat it, and clone the ENTIRE original drive to it using CCC.

(8) Configure System Preferences to use the new SSD as the startup drive

(9) Remove the old drive and reboot. Voila! New Ferrari!

Hope this is useful!


Thanks for the info, as I’m contemplating a similar move on my Mac Pro.

I’m a little way down your path already as years ago I had separated my home directory from the boot drive (for reasons entirely unrelated to this discussion). They are on the same physical drive (at the moment, but not always) but different partitions.

Your precautionary step of creating a spare “admin” account is critically important. If your regular home directory is unavailable for some reason, you will be able to log in to the alternate admin account to (hopefully) fix the problem. If you don’t have a spare account and your primary one is unavailable then you’re in a a very painful place, as the system will not ever complete booting and come up. You’re seriously “stuck”. The behavior was different under old versions of Mac OS X (maybe as late as Tiger)—in such a case the system would create a new, empty home directory in “Users” and the poor unfortunate user would think that everything had been erased!! A real heart-stopping moment, and it took me a while to figure out what was going on. It no longer does this (good) but it does mean that you need an alternate account.

Your “Users” directory should always remain on the boot drive, with the alternate account in it.

With regard to the iTunes issue ... I had tried having the media folder in a different location but things were unhappy. My solution was to move the whole iTunes folder out of the home directory and replace it with an alias. So all the iTunes things are in the same folder, outside of home directory, and ~/Music/iTunes is an alias that points there. The intended side-effect of this is that a copy (via FoldersSynchronizer) this whole folder on a portable drive works very nicely when plugged into my laptop.


Recently we started using dual SSD’s in our MacBook Pros with an incredible jump in performance. We removed the internal SuperDrives and put the second one in there. Our Art Directors LOVE IT!

We also started using the 40GB OWC drive in our MacPro’s for scratch drive and VM data.  We configured PhotoShop and Illustrator to dump their scratch drive data onto these, WOW!

Now were about to go to dual SSD drives in the MacPro’s for boot and scratch. We have been wanting to do this for a while, but been waiting for costs to come down to a reasonable price.


Simply wow!  I can’t understand why this whole process turned into such a complex operation that spanned days!

I have a 2009 Mini that had a 320GB HDD installed.  I decided to go with the 120GB OWC model.  At the same time i decided to replace the optical drive with a HDD sled.  I moved my existing HDD to the sled, installed the SSD, and began the very easy process of transferring files to the SSD.

Like many I used the 10.6 install DVD (had set up the old optical drive in an external USB case), and done a clean install on the SSD, creating my “admin” account in the process.

I then used Migration Assistant to move stuff from the HDD onto the SSD, which created my “user” acccount as well.  Of course I knew that this would pretty much fill up my 120GB drive so I didn’t select the Music, Movies, and Pictures folders.  When finished, the System, Applications, and the remainder of my user files took up 50GB, leaving a bit over half the drive empty.

Total time taken:  2-1/2 hours, most of which was doing the hardware swaps and installing the clean install of OS X.

I don’t consider myself as competent at such things as others but I fail to see how I managed this in such a short time where others are (perhaps unnecessarily) taking more complex routes to the same destination.


Great article, Ted - I’m seriously considering dropping an SSD in my tower, myself. OWC has apparently just recently dropped their prices again; possibly in response to Intel’s recent announcement of bigger, cheaper SSD’s. It’s a good time to get on board.

Wouldn’t it be just as well to use Time Machine to port your user account to the new drive, though?

Ted Landau

I fail to see how I managed this in such a short time where others are (perhaps unnecessarily) taking more complex routes to the same destination.

Well, for one thing, you have significantly less data than I do. It took me more time than you just for the waiting around part while data copied from one drive to another.

Second, your time estimate did not seem to include an erase/clean of your 320GB HDD ? and recopying of its data. Did you just leave the invisible (and now unneeded) System files etc. on the drive?

Third, you did not cite the time needed to set up new backups for your arrangement. Are both your SSD and HD now backed up to separate drives/partitions? Didn’t this take time?

Lastly, I had problems with Migration Assistant that you apparently did not have ? forcing me to start over with a new approach. This took time as well.

Ted Landau

BTW, if you’re looking for a good article on installing an SSD drive in a MacBook Pro (rather than a Mac Pro), Weldon Dodd published a “how-to” the same day that my article posted (a coincidence!).

He takes yet a different approach ? using symlinks to split the Home directory across both the SSD and HD.


@Ted Thanks for your considered response.  Here are my notes in that regard.

1.  Waiting time to copy from one drive to another.  Was this your data migration to the new drive?  Copying 60GB from the SATA HDD to the SATA SSD took very little time.  Sorry, I can’t recall how long but it wasn’t hours.

2.  Erase/clean of my 320 HDD.  No of course not.  That drive simply became my internal backup drive.  What’s to erase and clean?  If I wanted to, that can certainly be done at a later date and has no bearing (for me) on the time it took to get up and running with the SSD.  even so, that would have taken about half an hour.

3.  New backups?  I already had backups of my Pictures, iTunes, Movies folders on an already-functioning external drive.  No need to create new backups so no time involved.

4.  Yes, beginning again would certainly add to the time.  But two days’ worth?

Ted, please don’t get me wrong, I’m not trying to cast your article in a bad light, and I enjoyed reading the article.  I just think it’s at the extreme end of the spectrum.  The process should not take as long as it did for you and therefore your article might deter others less familiar with such things to forgo attempting such a project.

Please note:  I have no idea what you’re talking about when you get into the topic of “symlinks.”

Ted Landau

Erase/clean of my 320 HDD.? No of course not.? That drive simply became my internal backup drive

Yes. It becomes clear you started with a significantly different setup and had significantly different goals.

For example, once I moved the System Software from my hard drive to the SSD, I wanted to delete the System Software from the hard drive. That’s why I decided to erase it and start over with a clean drive. This appears not to have been relevant for you.

Different strokes for different folks, as they say. Or there is more than one way to skin this cat? Or whatever. smile


@Ted:  Heh-heh.  I totally agree with your last paragraph!  You had a particular goal in mind that involved a different set of steps.  I had another, with my own set of steps.

The important thing is, we both got where we wanted and are quite happy with our results (except for your Mig.Asst. hiccup).

Enjoy your weekend!


My approach was a bit different. I replaced the Dvd unit , that i used very rarely, and enclosed it in an Usb box. Then i used the two sata ports avalaible for the Dvd units for two 64g c300 crucial, very cheap nowadays.
As SSD?s dont have moving components, its enough to screw them to de Dvd ?s bays only in one side. The stay steady.
I created a Raid 0 unit.
Carbon copy cloned the original boot unit.
Imagine the speed…..


Hats off to you, Ted.

I admire not only your demonstrated geek prowess, but your pluck in braving the scary possibility of lost data.

When I heard you describe this on Chuck Joiner’s MacNotables, I found myself groaning aloud at each turn and twist, particularly the ones that I knew would not work. I have to admit, as much as I enjoy a challenge (and I do), I think I have reached a point in my professional life where my time is my most precious asset, and yes, I would have reached for the wallet and sprung for the extra moolah to get the larger drive.

Perhaps one day, in my retirement, in between hiking my trousers up over my navel, chasing the neighbours’ kids off my lawn, trying to recall where I left my teeth, and watching ‘Gran Torino’ for the umpteenth time (and shouting ‘You tell ‘em, Clint!’), I might be able to indulge, once again, in such geekdom.

Until then, I salute you, sir.

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