The perfect SSD and HDD hybrid MacBook setup

The SSD and HDD happily together, with plenty of space for more data. Note the separation of different categories of data, most suitable for either drive.

The performance of a Macbook pro by itself is quite amazing, but enthusiast know that the quest for higher specs never ends. It used to be that adding more memory (RAM) would be the best investment in increasing a machine’s performance and it sure still is one of the first things one should consider upgrading. With the introduction of solid state disks (SSD) however, replacing the magnetic hard-disk has become at least equally rewarding, if not even more. A typical 2.5 inch hard-disk will get about 60-90 MB/s in sequential read/write measurements, while a modern SandForce SSD on a SATA3 connection can easily get up to 400-500 MB/s. More importantly, seek times are dramatically lower on an SSD, given that the drive does not have to position a head physically on several disk platters. Since typical usage patterns on modern OS include loading many small files from completely disjoint regions of a mechanical hard-disk, an SSD can cut load times for a typical application to fractions of a second, whereas a mechanical drive would load data for seconds. However, SSDs are still much more expensive than mechanical drives, eclipsing $1 per GB, which makes them too expensive to keep your vast collection of music, pictures and movies on them. Fortunately, storing such files is more like keeping an archive of rarely accessed data and therefore there is no real benefit in storing hundreds of gigabytes of pictures of your cats, dogs or family on an SSD.

The following is a step by step guide on upgrading a typical Macbook with an SSD and preserving the old mechanical drive for rarely loaded data, such as your iPhoto pictures, iTunes music and movie folders. Some guides will recommend moving the whole /Users/<yourname> folder to the mechanical drive. Personally, I think that having parts of your user folder on the SSD will benefit performance, as many applications cache data in the ~/Library folder, and store settings and metadata in this location. The load time of applications can be improved if such data also resides on the SSD.

First, a couple of preparatory steps need to be performed.


a. Make sure you have a current backup

Needless to say that if you are dealing with moving data and manipulating your long-term storage system of your computer, you should make sure that your backups are up-to-date. The following guide has the potential to destroy all of your data, so beware before performing any of these steps. Safeguarding your data is YOUR responsibility!

b. Find out where your data lives

In order to make the right decision on how big of an SSD drive you should get, it’s probably best to know what kind of data takes up the most space on your drive. Data such as your iTunes library, movies or iPhoto library do not need to be placed on an SSD, as such data usually doesn’t load very often and when requested, the performance of a mechanical drive will just do fine. Applications like WhatSize can make it easier identifying your storage requirements.

WhatSize helps identifying where you’re storing most of your data

c. Get an optical bay adapter

These days, most people don’t use built-in optical drives anymore. There are some vendors out there manufacturing bays that will allow replacing the optical drive with a second hard-disk. If you want to keep your mechanical drive to store rarely accessed data, this is the way to go. MCE Tech sells the Optibay online. Make sure to get the right adapter for your Macbook, as some MacBooks have SATA interfaces, while older ones have a PATA interface for the optical drive and that would require you to get a bay that converts PATA to SATA, so you can keep using the SATA drive that came with your notebook.

d. Choose an SSD

New Macbook Pros come with a SATA3 interface, which will allow you to take advantage of new SandForce SSD drives. SATA3 has a theoretical transfer speed of 6 Gb/s. SandForce powered SATA3 SSD drives can deliver up to 500 MB/s in sequential data transfer rates, which is easily a 5-8 times improvement over a regular mechanical drive. When choosing the size, make sure you also have at least 20 GB or more left on top of your storage needs, as the OS performance starts degrading dramatically, if you run into low hard-disk space.

e. Have an external USB enclosure ready

Transferring the data from the original hard-disk to the new SSD is much easier if you have an external drive available, as it will reduce the amount of times you’ll need to disassemble your notebook. Now proceed with attach the USB enclosure to your Macbook.

That’s it. We’re done with the preparations. Let’s move on to the real migration work.

1. Partition the new SSD drive

Use Disk Tool from the Utilities folder to partition the new SSD. Make sure to choose “GUID Partition Table” under Options of the Partition tab before creating the new partition. Name the new partition to “Macintosh HD” in order to preserve the naming of the drives and select “Mac OS Extended (Journaled)” as the file system type. Hit “Apply” to finalize your changes.

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Choose GPT when partitioning to ensure that your drive is bootable

2. Transfer all data using Carbon Copy Cloner

While there are other tools available for this, Carbon Copy Cloner is a great and free (donation ware) tool that allows you to efficiently clone your original drive to the SSD, without requiring any re-installation of Mac OS X. I’ve used this tool for years now and it has never failed me so far.

When running CCC make sure to exclude your media data folders. Exclude the following folders:

  • /Users/<yourname>/Movies
  • /Users/<yourname>/Music
  • /Users/<yourname>/Pictures

Deselect your media folders when cloning your data from the HDD drive to the SSD

3. Make room for Bootcamp and Windows (optional)

If you are interested using some of the prospective available space of your mechanical drive, you should consider preparing your bootcamp partition now. Windows requires the optical drive to be attached to the SATA bus of your machine and won’t allow you to install from an externally attached USB drive. Therefore it’s most advisable to perform the Windows installation at this time, so that you won’t have to disassemble your machine multiple times. This guide won’t go into details on how to install Windows on your Macbook, as there are plenty of good guides elsewhere. Just make sure to detach your SSD drive from the USB port before proceeding. That will ensure you’re not accidentally removing the newly created parathion on the SSD drive or re-format it inadvertently.

4. Don’t reboot into Mac OS X

Once the main hard-disk is cloned, you should avoid continuing to use or rebooting into Mac OS X as changes won’t be present on your SSD. If you’ve installed Windows in the previous step, you can make sure to avoid booting to Mac OS X by pressing the “alt” key during startup. That will allow you to choose the Windows partition instead.

5. Remove primary drive and remove built-in superdrive

It’s time to replace your primary drive with the SSD and install the optical bay replacement to hold your mechanical drive. Follow the guide that came with your optical bay replacement or check out the many guides you can find by searching Google.

6. Your first boot from the new SSD

It’s time to boot Mac OS X from the SSD for the first time. When turning on your notebook, make sure to keep the “alt” key depressed. That will allow you to choose from which drive to boot. If you’ve installed the SSD as the primary drive and put the mechanical drive into an optical bay adapter, you will see two “Macintosh HD” volumes available. The left volume is the first from the SSD. Choose the left “Macintosh HD” volume and hit return. You should already notice by now that you’re booting from the SSD, as your usual boot time should be cut down dramatically.

7. Rename the mechanical drive to “Data”

Beware that any removals should only be performed if you are confident that your data is available on a backup. The following steps have some severe data loss potential! Proceed with caution and at your own risk!

Once Mac OS X is fully booted go to the Finder and hit control-shift-g. Enter “/Volumes” and hit enter.

Go to the /Volumes location using the Finder’s goto function

You should see a “Macintosh HD 1” volume, the old mechanical drive, which you can rename to anything you like, or just “Data” for the purpose of this guide. From here you can also proceed in removing all System directories such as “Applications”, “Libraries”, “System” and so on, as these directories are fully cloned and available on your SSD. Just ensure not to remove the “Users” directory, as it contains all your pictures, movies and music that you have not transferred to the SSD.

8. Move your media folders to the new Data volume

Go to the finder again and navigate to your old Users directory. Hit control-shift-g and enter “/Volumes/Data/Users/<yourname>” . Grab the Movies, Pictures and Music folders and drag them to the “/Volumes/Data” location. Then you can proceed in removing the rest of the “Users” folder from the old drive, as anything else should have been moved when cloning the drive initially.

9. Redirect your Music, Movies and Pictures folders to the Data volume

Open a Terminal window and type the following commands:


Create the symlinks to your Data volume

These commands will create symlinks from your user folder to the mounted Data volume. Symlinks are like shortcuts redirecting data to another location on the drive. iPhoto, iTunes and iMovie will continue to think that your data is in its usual location and the applications won’t need any reconfiguration to access the data from the mechanical drive. Additionally, if you’ve set up Time Machine to perform backups, TM will follow these symlinks and continue to backup your data as usual, despite being located on a different drive than the operating system.

10. Restart your backups

Now would also be a good time to ensure your backups are up-to-date again. If you’re running Time Machine or any other backup, make sure to check that the backups are being performed as expected.

11. Done!

You’re now a lucky owner of a hybrid SSD and HDD setup. Access to your applications should be dramatically faster, while not wasting precious SSD storage on rarely accessed data.

Pictures, Music and Movies all mounted on the mechanical drive

I hope this guide was helpful to you. If you have questions or contributions, feel free to leave a comment.