Hey guys! I'm a longtime PC user and recently went to "the dark side" when I was given a 13" rMBP for work back in November and was instantly smitten with Mac and OS X. Being an old Unix guy, I just love being able to go to Terminal and really see what's going on. The OS X GUI took a little getting used to, and I'm still working on keyboard shortcuts, but I'm getting there.
So, anyways, after a few months of using the laptop, I was ready to go the Mac on my home desktop. I was originally planning on going with a Mac Mini and using the existing dual 24" monitors I already for the PC and saving a few bucks, but I really wanted something with the Haswell processor and I got tired of waiting for the Mini to refresh. After weeks of contemplation and research, I was ready to pull the trigger on a 21.5" iMac, but when the time came to make the purchase, I just couldn't wait for Apple to build the system for me and I had to pick something up *NOW*!
I walked out of the Apple store with a 27" iMac, knowing full well I'd be able to upgrade the RAM myself (which I did, quite easily). Unfortunately, that meant no SSD or Fusion drives, so I went to work on checking out my options.
Having only had this monster of a screen sitting on my desk for one week, I wasn't ready to pull it apart and attempt to install an SSD myself (but, maybe next year...), so I decided I'd pick up an external SSD with Thunderbolt support and see what I could make it do. There aren't a whole lot of options out there, and they all run about the same price (depending on size), so I decided on the LaCie Rugged 120GB Thunderbolt/USB drive (http://www.amazon.com/LaCie-Rugged-Thunderbolt-Series-9000291/dp/B00A3G461K) figuring the extra USB3 interface would give me some more options for this device in the future. I wasn't too keen on the bright orange rubber casing, but was pleasantly surprised when I received the unit that it easily comes off revealing a relatively attractive (if plain) brushed aluminum case.
Next up was deciding how I really wanted to use this thing. I like the idea of the Fusion drive and letting the OS do the dirty work of deciding what belongs on the fast drive and what belongs on the slower drive. My findings with Blackmagicdesign's Disk Speed Test (using 5GB stress size), though, really surprised me....
This is the stock internal 1TB 7200 RPM drive in the 27" iMac:
![DiskSpeedTest-IntHDD.png]()
The first surprise was the Write speed on the Thunderbolt connected SSD. Read speed was great - over double the read speed of the internal drive. Write speed, though, was just slightly slower:
![DiskSpeedTest-ExtSSD.png]()
Next I created Fusion drive using the Thunderbolt connected SSD and the internal HDD using this great article from OWC (http://blog.macsales.com/17624-os-x...tup-option-for-non-fusion-drive-equipped-macs). Unfortunately, I somehow lost the benchmark details from the "clean" Fusion drive (with about 50GB of OS, Apps, and Documents). In my mind, that doesn't really matter anyways (in regards to determining Fusion performance) -- what is more important is what happens after you fill up that initial SSD and how the OS performs swapping data to/from drives and managing performance. So, I copied 200GB of misc. crap to the Fusion drive -- music, movies, pictures, etc. After that, Write performance fell through the floor, but Read performance still acceptable:
![DiskSpeedTest-fullDisk.png]()
(I ran the test immediately after copying the data, and approximately 8 hours after copying the data - assuming/hoping that the OS would optimize the data in that time. Probably a bad assumption, since I wasn't actively reading/writing the data, so OS X really doesn't know what is important and what isn't. Unfortunately, it would appear to assume that *everything* is important - at least initially - but still, 35.8MB/s Write speed? That's crazy slow!)
OK, what happens if I remove that 250GB of crap (and empty the Trash)? One would think that, since only 50GB is being used, the OS would go back to using the SSD first. Apparently not.... (again, after an 8 hour wait...)
![DiskSpeedTest-afterCleanup.png]()
It got even slower -- both Writes and Reads, and rather significantly slower than the stock drive. In my mind, that's simply unacceptable. But what does this mean? Many people have speculated that creating a true Fusion drive with an external device is not possible. My tests would seem to prove that. I'd love to see how my tests run on a true Fusion drive.
Armed with this information, I'm going to run with the Boot and System files from the External SSD and use the internal drive for User files. This has been a great learning experience for me, a perfect opportunity to really learn the ins-and-outs of TimeMachine (and SuperDuper, which was a much faster backup/restore option), building boot devices, installing OS X, etc. Hopefully this will be of some use to others out there.
Summary:
So, anyways, after a few months of using the laptop, I was ready to go the Mac on my home desktop. I was originally planning on going with a Mac Mini and using the existing dual 24" monitors I already for the PC and saving a few bucks, but I really wanted something with the Haswell processor and I got tired of waiting for the Mini to refresh. After weeks of contemplation and research, I was ready to pull the trigger on a 21.5" iMac, but when the time came to make the purchase, I just couldn't wait for Apple to build the system for me and I had to pick something up *NOW*!
I walked out of the Apple store with a 27" iMac, knowing full well I'd be able to upgrade the RAM myself (which I did, quite easily). Unfortunately, that meant no SSD or Fusion drives, so I went to work on checking out my options.Having only had this monster of a screen sitting on my desk for one week, I wasn't ready to pull it apart and attempt to install an SSD myself (but, maybe next year...), so I decided I'd pick up an external SSD with Thunderbolt support and see what I could make it do. There aren't a whole lot of options out there, and they all run about the same price (depending on size), so I decided on the LaCie Rugged 120GB Thunderbolt/USB drive (http://www.amazon.com/LaCie-Rugged-Thunderbolt-Series-9000291/dp/B00A3G461K) figuring the extra USB3 interface would give me some more options for this device in the future. I wasn't too keen on the bright orange rubber casing, but was pleasantly surprised when I received the unit that it easily comes off revealing a relatively attractive (if plain) brushed aluminum case.
Next up was deciding how I really wanted to use this thing. I like the idea of the Fusion drive and letting the OS do the dirty work of deciding what belongs on the fast drive and what belongs on the slower drive. My findings with Blackmagicdesign's Disk Speed Test (using 5GB stress size), though, really surprised me....
This is the stock internal 1TB 7200 RPM drive in the 27" iMac:
The first surprise was the Write speed on the Thunderbolt connected SSD. Read speed was great - over double the read speed of the internal drive. Write speed, though, was just slightly slower:
Next I created Fusion drive using the Thunderbolt connected SSD and the internal HDD using this great article from OWC (http://blog.macsales.com/17624-os-x...tup-option-for-non-fusion-drive-equipped-macs). Unfortunately, I somehow lost the benchmark details from the "clean" Fusion drive (with about 50GB of OS, Apps, and Documents). In my mind, that doesn't really matter anyways (in regards to determining Fusion performance) -- what is more important is what happens after you fill up that initial SSD and how the OS performs swapping data to/from drives and managing performance. So, I copied 200GB of misc. crap to the Fusion drive -- music, movies, pictures, etc. After that, Write performance fell through the floor, but Read performance still acceptable:
(I ran the test immediately after copying the data, and approximately 8 hours after copying the data - assuming/hoping that the OS would optimize the data in that time. Probably a bad assumption, since I wasn't actively reading/writing the data, so OS X really doesn't know what is important and what isn't. Unfortunately, it would appear to assume that *everything* is important - at least initially - but still, 35.8MB/s Write speed? That's crazy slow!)
OK, what happens if I remove that 250GB of crap (and empty the Trash)? One would think that, since only 50GB is being used, the OS would go back to using the SSD first. Apparently not.... (again, after an 8 hour wait...)
It got even slower -- both Writes and Reads, and rather significantly slower than the stock drive. In my mind, that's simply unacceptable. But what does this mean? Many people have speculated that creating a true Fusion drive with an external device is not possible. My tests would seem to prove that. I'd love to see how my tests run on a true Fusion drive.
Armed with this information, I'm going to run with the Boot and System files from the External SSD and use the internal drive for User files. This has been a great learning experience for me, a perfect opportunity to really learn the ins-and-outs of TimeMachine (and SuperDuper, which was a much faster backup/restore option), building boot devices, installing OS X, etc. Hopefully this will be of some use to others out there.
Summary:
Code:
Desc Write Read Link
Stock Internal 1TB 7200 RPM Drive 170.1 181.5
External Thunderbolt LaCie 120GB SSD 162.1 382.6 http://www.amazon.com/LaCie-Rugged-Thunderbolt-Series-9000291/dp/B00A3G461K
DIY Fusion (Thunderbolt/Internal) - 250GB used 35.8 227.6
DIY Fusion (Thunderbolt/Internal) - Cleaned Up 30.6 165
External USB3 Matsunichi 1TB 73.1 73.1 http://www.amazon.com/Matsunichi-Portable-External-Drive-DM256-BK-1TB/dp/B00EMDP09M1
