If you read this blog for some time you may have come across my story on upgrading my MacBook Pro Late 2008 by adding an SSD to it. There were a couple of other things that I’d been doing but didn’t blog about, frequently shuffle around programs to make the most of the SSDs, that’s the story I am about to tell here. In this post I am assuming that you are familiar with Unix/Linux file naming conventions, and that you have similar constraints that I have as explained in my disk upgrade story earlier in this blog.
To recap the posting I’m referring to, I had deliberately chosen a smaller SSD (60 GB) to keep the costs down, but that meant that I had to keep a lot of large files in the slower HD drive. Given the difference in performance between the two drives, I was wondering how I could somehow make that SSD work harder for me. So I came up with a simple routine, which I didn’t think much of at the time. There are times when I am more frequently programming, and other times when I am using graphical tools or launching virtual machines (Ubuntu, Windows xx), so I would swap around those programmes and large folders between the two disks in an very simple way.
Mac OSX has a feature that comes in handy here: applications may be installed in the system by placing them in the folder “/Applications”, or installed only for one user when placed in a folder called exactly “Applications” in the user’s home folder, which in Unix is “~/Applications”. Knowing this, I laid out my two disks to take advantage of it. In case of data files, even virtual machines you simply have to ‘forget’ any cached uses and get the application to load it by giving it a direct folder reference. Parallels is an exception, it is sensitive to virtual machine images being moved around and might fail to load them. While loading it, you have to tell Parallels that you have moved a VM, it will do the right thing, otherwise you may damage your VM. I won’t go into that here.
When I am frequently using Xcode I would move it to “/Developer”, I would move other large software like Adobe FireWorks from “/Applications” to “~/Application” and create symbolic links to mask these changes. When I enter another period where I don’t develop or do it less frequently, I swap those large folders around again and restore the original links. This may sound convoluted but it isn’t, it’s just a couple of lines of shell scripts that would run a couple of minutes then you’re done. The trigger for starting this folder dance was that, when my SSD had less than 10GB free space the machine could run out of virtual memory (remember I have 8 GB RAM on this machine), so I had to try and keep that disk above 11 GB free space at all times.
The main drawback I run into was when I tried to do the same with iTunes and iPhoto (my large photo library), I run into problems and had to stop that, but it worked fine for running frequently used programs. I also used to run “Fix Permissions” after each shuffling of large folders, this made my technique even slower, so I only tended to do it once every other week and sometime forgot to revert things when I changed daily work routines.
To summarise, if you have a MacBook Pro Late 2008, like I have, or any Mac that is equipped with both an SSD and an HD, you can make the SSD work harder for you and gain some performance by applying this super simple folder shuffling technique. You can even do it with large data files that you may be opening several times a day or in relatively quick successions. I initially came up with the idea by thinking about the way detachable storage works, nothing special. The technique is most effective if you have a relatively stable work routine over several days or weeks.
I recently saw an article by ArsTecnica on Apple’s Fusion Drive, which seemed to be indicating a somewhat similar technique but obviously a sophisticated and robust one that is also transparent to the user. This technology will be available in their new line of MacBooks, I didn’t really follow that event. t thought of telling this story, in case someone happens here while looking for tips. I have to say though, I read lots of stories about SSD failure rates, I experienced one with my older Time Capsule external storage drive, it was a LaCie 1TB drive, one day it simply stopped responding, no warning whatsoever, gone for good without any (noticeable) incident. So, although SSD are exciting, and I’ve been enjoying a performance boost since I installed mine, there’s a little nervousness that it may surprise me one day. I wanted to warn you, the reader, about this risk because, you just never never know.