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A window into the Digital Life of Bryan Vyhmeister

OWC Aura Pro Express SSD for MacBook Air: Migration and the Recovery Partition

On Christmas day, I ordered an OWC Aura Pro Express SSD for my 2010 11-inch MacBook Air. When I originally purchased this MacBook Air, I wanted to keep things as inexpensive as possible to start out with since I was planning to upgrade to the Aura Pro Express SSD from the beginning. To that end, I had purchased the 1.4GHz Core 2 Duo 11.6-inch MacBook Air with only a 64GB SSD but with the absolutely essential 4GB memory upgrade. One thing led to another and I had not upgraded the SSD for almost exactly a year. That is, until now.


More photos are in my Flickr set of the installation.

Although I was certainly able to survive without more than 64GB of storage, it meant that things like all but one virtual machine, my mobile iTunes library, Aperture library, and larger downloads all had to live on an external USB 2.0 drive. This situation was always frustrating because I like simplicity and minimalism and carrying an external drive essentially kills those preferences.

In reality, it was not as bad as I thought it might be. Most of the time I was working at my desk anyway which meant using my other systems more anyway. In the last several months I have started working more from unusual locations that I would not normally work from. This has led me to be mobile more often and has made the inconveniences of an external drive a true irration and hindrance. It was time for the solution at last.

Cost Analysis

I have been watching the prices on the Aura Pro Express SSDs during the last year and they have steadily dropped over that time. In addition, OWC has also launched 6G Aura Pro Express SSDs to go along with the 6Gb/s SATA III interface on the 2011 MacBook Air models.

Although I suspect the 6G Aura Pro Express works fine in a 2010 MacBook Air even though the 2010 model has a 3Gb/s SATA II interface, OWC states on their website and when I called that the 6G version is only compatible with the 2011 MacBook Air. Since I am planning to upgrade to an Ivy Bridge MacBook Air this year, the 6G Aura Pro Express would be a better option in some ways. However, my current 2010 model will be passed on to my wife who has nearly filled her 128GB SSD on her older MacBook Air.

The prices on the 3G Aura Pro Express SSDs are $264.99 for the 180GB model, $399.00 for the 240GB model, and $1079.00 for the 480GB model. The 6G versions are slightly more at $259.99 for the 120GB model and $499.99 for the 240GB model. Looking at the cost per gigabyte of the 3G version, the 480GB model is immediately out of the running. I have no interest in spending over $1000 on an SSD for a computer I will be replacing in a few months.

The 480GB model works out to be $2.25 per gigabyte, the 240GB model is $1.66 per gigabyte, and the 180GB model is $1.47 per gigabyte. By contrast, the 6G models are $2.08 and $2.17 per gigabyte for the 240GB and 120GB models respectively. The 180GB 3G model is definitely the best value in terms of cost per gigabyte. This sequence is slightly unusual given that most often, as with the 6G models, the mid-tier models of a given storage device are cheaper per gigabyte than either the entry-level models or top-end models. I suspect the 180GB is the best value because it probably sells the best given the relatively high prices of SSDs in general.

Cloning and Recovery

NOTE: Before you start this process, I would strongly suggest that you turn off FileVault 2 if you have it enabled and wait for decryption to complete. This took about 10-15 minutes for me. Although I did not test what would happen with it enabled, FileVault 2 would very likely cause problems or significantly change the steps required below.

Based on this analysis, I ordered the 180GB 3G Aura Pro Express SSD. Since I ordered it on Christmas day, it did not ship until the 27th and with the inexpensive UPS 2nd Day Air shipping, arrived on the 29th. I immediately set out to get it installed. Prior to Mac OS X Lion, it was relatively easy to use a great tool like Carbon Copy Cloner or SuperDuper to clone your old drive to the new one or to an intermediary drive to facilitate the upgrade. Lion changed all that since it now has a recovery partition to facilitate a reinstall of Lion or perform various system maintenance since physical media is no longer included with recent Mac models.

While it would seem simple enough to just clone the recovery partition, it is a more complex issue since the recovery partition is hidden and does not normally show up in Disk Utility. Fortunately, some enterprising Mac users have found some ways to solve this problem. OWC suggests two ways of installing Lion on your new Aura Pro Express SSD.

The first method, Apple’s Internet Recovery Mode, was of no interest to me since it is fairly slow and also causes a complete erase of your original SSD in the process. The second method involves a multi-step process.

  1. Make SURE you have a Time Machine backup or clone of your data (from either the Apple factory stock flash drive or OWC Aura Pro Express SSD) on an external drive. We will refer to this drive as Drive #1.
  2. Boot to the recovery partition on the stock drive by holding down Command R during a restart or boot process.
  3. Use Disk Utility to do a restore on a separate external USB drive. DO NOT use the same external drive that was used for your Time Machine or clone backup. We will refer to this drive as Drive #2.
  4. Replace the MacBook Air’s stock flash drive with the OWC Aura Pro Express SSD.
  5. Boot to the USB Drive #2’s recovery partition.
  6. Use Disk Utility to do a restore to the OWC Aura Pro Express SSD.
  7. Restart or Boot to the OWC Aura Pro Express SSD.
  8. Run Apple Migration Assistant to clone your data from Drive #1.

This sequence seems somewhat inefficient but is probably the easiest method for an inexperienced user who want so avoid Internet Recovery Mode. I started with step number one. Naturally, I already maintain a Time Machine backup of my MacBook Air. I plugged in that drive and made sure it was up to date before starting this process.

I next located a 120GB SATA 2.5-inch hard drive I had sitting around and stuck it in an Icy Dock 2.5-inch USB 2.0 enclosure. I formatted this drive with the defaults which is a GUID Partition Table and a single partition. I then went to the partition tab of Disk Utility with the physical drive selected and clicked the plus in order to add another partition. I named the partition Recovery HD and selected the smallest allowable size of the partition by typing .65 in the size field. Disk Utility changed this to 1.07GB. I then applied this change and now had two partitions on the external drive.

I did some Google searches looking for a solution for cloning the recovery partition itself which brought me to a MacFixIt article with just the info I needed. This article brought to my attention a system setting for Lion that turns on a debug mode in Disk Utility that allows you to see all partitions if the “Show every partition” option is selected in the Debug menu.

defaults write DUDebugMenuEnabled 1

Once the above flag was turned on from Terminal, I could now clone my Lion recovery partition. In order to actually accomplish the recovery partition clone, I selected the now-visible recovery partition on my MacBook Air’s original SSD and selected the “Restore” tab within Disk Utility. The recovery partition automatically showed up as the source and then I quickly dragged the external drive’s Recovery HD to the destination field. I then clicked “Restore” which only took less than a minute.

I now had a recovery partition on the external drive. I then rebooted the MacBook Air and held down the Option key in order to select the USB 2.0 drive’s recovery partition. After it booted just fine, I selected Disk Utility in the recovery partition interface and cloned my regular SSD to the external drive. This process took just under 45 minutes which is limited primarily by the USB 2.0 bus. When this was completed it was time to install the Aura Pro Express in my MacBook Air.

I have not up to this point opened the case of the MacBook Air because I have not had any need to do so. I was pleasantly surprised at how incredibly easy this process was. All I had to do was remove the screws around the bottom plate of the MacBook Air and then I had ready access to the SSD. Removing one screw allowed me to replace the stock 64GB SSD with the Aura Pro Express 180GB SSD and then a quick replacing of the bottom plate and screws and I was ready to get back to work.

I once again booted up from the USB 2.0 drive’s recovery partition which brought me to the recovery menu. I selected Disk Utility and formatted the new Aura Pro Express as a single HFS+ (Journaled) partition. At this point I also used the same procedure as previously to create another 1.07GB partition on the Aura Pro Express for the recovery partition. I then cloned the USB 2.0 drive’s recovery partition to the Aura Pro Express. While this did work, the partition is bigger than the original recovery partition (650MB) and, for some reason, shows up as two different recovery partitions when booting up and holding the Option key. I would not do this step if you are in the same situation but instead create an all new recovery partition.

Creating a New Recovery Partition

I’m not interested in having an odd recovery partition that does not work correctly. That led me to search for other solutions. I came across a blog post detailing a way to recreate the recovery partition properly. The blog post information originally came from a post on Google+ detailing the solution.

First off, you need the Lion Recovery Update released by Apple on October 12, 2011. Once you have the file named RecoveryHDUpdate.dmg, follow these steps in the terminal to recreate your partition. Before you do this, though, I would recommend you boot back into the USB 2.0 drive’s recovery partition and run Repair Disk from Disk Utility on your main SSD partition. Initially, creating the recovery partition failed for me because I had some catalog errors after cloning my data from the USB 2.0 drive to the Aura Pro Express SSD.

The following commands entered in Terminal will accomplish the process. The explanations following each command should make it clear what is being accomplished at each step. These commands assume your working directory is your home directory. This also assumes that the RecoveryHDUpdate.dmg file is in Downloads in your home folder.

hdiutil attach ~/Downloads/RecoveryHDUpdate.dmg

This mounts the RecoveryHDUpdate.dmg as a volume so you can access files from it.

pkgutil --expand /Volumes/Mac\ OS\ X\ Lion\ Recovery\ HD\ Update/RecoveryHDUpdate.pkg /tmp/RecoveryHDUpdate

This command expands the installer package contained on the RecoveryHDUpdate.dmg and installs it in the RecoveryHDUpdate directory in /tmp where the system stores temporary files which are automatically cleared at the next system restart.

hdiutil attach /tmp/RecoveryHDUpdate/RecoveryHDUpdate.pkg/RecoveryHDMeta.dmg

This command mounts the RecoveryHDMeta.dmg contained inside the RecoveryHDUpdate.pkg installer package as a volume.

/tmp/RecoveryHDUpdate/RecoveryHDUpdate.pkg/Scripts/Tools/dmtest ensureRecoveryPartition / /Volumes/Recovery\ HD\ Update/BaseSystem.dmg 0 0 /Volumes/Recovery\ HD\ Update/BaseSystem.chunklist

This command runs the dmtest script with the required parameters to actually create the recovery partition. Note that as part of this process, your disk is checked for errors. If any errors are found, this process will fail and a recovery partition will not be created. Like I mentioned earlier, I would suggest you restart and boot from the USB 2.0 drive’s recovery partition and Repair Disk before attempting to create the recovery partition.

A substantial amount of output should go by in your terminal session and at the very end you should see the last line state simply.

Creating recovery partition: finished

If you see another line after this with an error message, something went wrong and you will not have a proper recovery partition. In order to verify that your recovery partition exists, run:

diskutil list

The output should contain the following at the top although the mounted disk image files will show up later in the output.

   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *180.0 GB   disk0
   1:                        EFI                         209.7 MB   disk0s1
   2:                  Apple_HFS MacBook Air SSD         179.2 GB   disk0s2
   3:                 Apple_Boot Recovery HD             650.0 MB   disk0s3

If you do not have partition number 3 of type Apple_Boot and name Recovery HD, something went wrong. Once you have verified that your disk0 output looks like the above, you can eject the disk images and do some final tasks before restarting. Run:

hdiutil eject /Volumes/Recovery\ HD\ Update
hdiutil eject /Volumes/Mac\ OS\ X\ Lion\ Recovery\ HD\ Update
sudo touch /Library/Preferences/SystemConfiguration/
sudo kextcache -f -u /

The first two commands eject the two mounted disk images, the third command updates the modification date on the file, and the final command updates system caches. The final step is to reboot your system and make sure you can boot into the recovery partition.

Clear Your Caches

Assuming everything is working fine, I would still suggest you use a utility like OnyX to clear you system caches including dyld’s shared cache and all your standard system caches. A couple days after the migration, I started having trouble connecting to my typical wireless networks but clearing these caches solved the problems.

Everything should be working perfectly now. I did have to setup Dropbox again which took all of ten seconds but otherwise everything has worked absolutely perfectly for me. My saved browser windows and everything all came right back up as though I was still on the old SSD. My experience in the first few days of the Aura Pro Express SSD has been great. I have had several VMs running without issue. I was able to move my mobile iTunes library and Aperture library back onto my SSD from the external drive. Performance has been very good.

Perhaps I should have done this upgrade much earlier. It was very much worth it. The price of an Aura Pro Express SSD is better than it has ever been before. OWC’s site has all the details.