Can you expound upon that. I'm not sure I understand why an app sitting on the flash portion of the Fusion drive will open up slower then if you split up the drive.
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Case For Unfusing the Fusion Drive
- Thread starter varian55zx
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Thanks for further clarifying, varian55zx. One question; My preferences pane opens with one bounce. Photoshop opens after at least three bounces. Can you confirm that Photoshop opens in just one bounce now?
I've seen videos on YouTube where, e.g. the new Macbook opens Photoshop and similar apps in just one bounce. It's instantly loaded (under 1 second).
I've seen videos on YouTube where, e.g. the new Macbook opens Photoshop and similar apps in just one bounce. It's instantly loaded (under 1 second).
Thank you for the question. My explanation for it again lies within the block storage aspect of the fusion technology.
Say you use Photoshop. Even I use photoshop occasionally. Many blocks of the app itself (and any files associated with the app), will be on the SSD, and presumably many will be on the HDD.
Photoshop is opening in one bounce for me now, without a doubt, under 2 seconds, and possibly, approximately 1 second if I were to time it. As a fusion user I will assume System preferences takes 2 bounces for you. It takes one for me with the split unless my computer is under heavy load.
What I can do is provide anecdotal examples that any fusion user can relate to. Again, I see the explanation lying within the block storage aspect of the fusion. I don't know what else it would be.
Take for example your Applications folder. Another thing that subtly bugged me about the fusion (and again, the fusion is still undoubtedly good), is the fact that when you opened the applications folder, the file size column took time to load. Of course that is because many, many blocks of all the various apps (presumably, even the 'frequently' used ones), are on the HDD. Once the HDD can communicate back the necessary information, the file sizes show in finder.
Well, with any SSD, they just show instantly. Even my early 2013 MacBook Pro shows the application file sizes, and all other data, instantly.
The 128 SSD MacBook (which is not a good machine), shows them instantly.
So it is subtleties like that that you are gaining time with, with the split.
As a frequent web browser, possibly one of the most noticeable improvements, is the loading time for web pages. It's instant. It's so much faster. That, in itself, has a very good argument for being "experience changing".
Another obvious area I'll add, is navigating through the various panes in System Preferences. For anyone who has been using OS X pre-SSD days, you probably know how slow that used to be. That was just a slow set of tasks whenever you ended up initiating them on one of the old HDD Macs. The Fusion drive was much faster, but running off the SSD of the fusion drive alone is instant.
It's a long time since I read technical information. Bookmarked, but I can't recall whether it's definitive: Apple Fusion Drive—wait, what? How does this work? | Ars Technica (2012-10-23, highlights). Also, found today: Splitting the Fusion Drive - A geek's tale - Ars Technica OpenForum (2013-06-20).
Maybe too geeky (not casual) for you, a couple of mentions of L2ARC: https://forums.macrumors.com/posts/20632103 (2015) and https://forums.macrumors.com/posts/22924568 (2016).
If you take an interest in ZFS, see https://forums.macrumors.com/posts/20613992 and https://forums.macrumors.com/posts/22922936 …
With or without ZFS: if you're interested in measurements of performance, consider the Intech stuff.
See the Ars Technica article; attention to the pink highlight.
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Thanks for expounding on your thesis, so basically your position is that its quite possible that larger applications such as Photoshop (especially due to plug-ins) will span across data blocks and potentially have some on the flash storage and others on the hard drive.
Fair enough, that makes sense and its definitely something to consider.
I guess if one thing is motivating me to split my drive up, its the unnecessary wear and tear as OS X shuffles the data blocks around.
I don't know what else it would be.
Something has to cause the slower speeds in the SSD vs fusion, even seen in commonly used apps, and I believe that to be the likely cause.
I know I have suggested the notion that SSDs slow down as they fill up, I still believe that is true, but I have come across several articles that are in support of that.
If that is indeed true, that would be another factor. I'm running on the 120gb SSD at about half its capacity, and the speed difference is apparent. I continue to be happy with the split.
How much difference are we talking?
As I dwell on this topic, and I've been thinking about this on and off, since I bought my iMac back in November, I always come to the same conclusion - not un-fusing the drives. I'm not criticizing your actions, but I think for me, the benefits do not out weigh the headaches and extra work needed.
depends on the person. I think it is a lot, but I consider very small amounts of time to be a lot in terms of the storage speed debate.
Everything is faster. There isn't a single task that isn't performed faster now. You're saving fractions of seconds or even seconds everywhere, app opening, web page loading, and anything within the apps.
If a small time save like that (which again, I personally don't think it's small), isn't that appealing to you, then there probably wouldn't be any need to do the split. In my case, the proposition of being able to have those small time saves was highly appealing to me, so I did go forward with the split and I turned out to like it better.
SSDs have to erase sectors before new data can be written to them. Over provisioning guarantees that there can be some sectors already erased and ready to go. Empty file system space combined with TRIM results in lots of pre-erased sectors.
Also keep in mind that wear leveling means existing filled sectors need to be moved around to other sectors. Potentially, every time you write to the SSD, sectors are getting moved around (and erased and then written with the new data.)
I don't see the speed increase being large enough to justify the increased complex setup. Granted my needs are such, that there is a higher complexity due to Boot Camp, but even ignoring that, I'd say that if Fusion adds a second or two to Photoshop starting up is small. I see 2 1/2 bounces to start up Excel. So if a split Fusion drive makes that faster even by 50% (1 1/4 bounces) then that improvement in the scope of things rather minor.
I understand you need to set up the computer that best fits your needs, and I'm quick to point out, that I'm not being critical of that. In fact, as I stated a few times, I've debated splitting this up myself but every time I come close to doing it. I find the benefits do not outweigh the downsides.
So are you saying that because the drive was recently split up and reformatted people will see the best performance and then as time goes on, it will slowly degrade (though still incredibly fast compared to a hard drive)?
The only thing keeping me from splitting up the two drives at this point is the small size of the SSD. I have a Samsung Evo Pro 128 GB in my Mac Pro serving as a boot drive and it fills up incredibly fast. I have to clean it up at least once every couple of weeks and it's tiresome. In contrast, I have a Macbook Pro Retina with 256 GB SSD and I am having a hard time filling it up. On neither do I save photos, documents, movies and such. So, had the iMac had 256 GB SSD, I'd have done it in a heartbeat. With only 128 GB, I am still reluctant and just don't know whether the gain is significant enough for my personal use case.
The proper fix is for apple to make the fusion drive caching more intelligent, if it isn't working well already.
A proper SSD cache setup can put individual blocks in cache whereas with filesystem management you can only move entire files. If the algorithm is intelligent enough it should outperform you quite easily.
Comparing 2 vs. 2.X seconds to load photoshop means nothing if you are then finding that you're losing significantly on other performance aspects. Throw a heap of random write workload at your machine and you need to pick in advance where it goes. A fusion setup can (potentially, if apple are not already doing this) serialise all that with the SSD before committing to disk in a big sequential write.
Enterprise arrays have been doing this for years. If apple are not doing it already, you can bet they will do in future OS X releases.
A proper SSD cache setup can put individual blocks in cache whereas with filesystem management you can only move entire files. If the algorithm is intelligent enough it should outperform you quite easily.
Comparing 2 vs. 2.X seconds to load photoshop means nothing if you are then finding that you're losing significantly on other performance aspects. Throw a heap of random write workload at your machine and you need to pick in advance where it goes. A fusion setup can (potentially, if apple are not already doing this) serialise all that with the SSD before committing to disk in a big sequential write.
Enterprise arrays have been doing this for years. If apple are not doing it already, you can bet they will do in future OS X releases.
I use it as a boot drive and have all the apps installed on it. I have no idea why it fills up so fast. I use Onyx to clean it up every two months or so. Do you mean the /user/ directory? If so, yeah, I haven't messed with that.
Its quite possible that ~/Library is filling up, i.e., your iPhone backups go there, emails and attachments etc. My ~/Library folder 48 gig.
Download and use OmniDiskSweeper. It will provide a sorted list of what's consuming your space.
It's a matter if you want SSD speeds vs fusion speeds.
file management for me hasn't really become any less convenient.
My user experience hasn't changed (I guess I have aliases for folders on my desktop now instead of the actual folders themselves), and I'm still loving the speed improvement.
Say you split them and just put Windows on the HDD, it's the same as what you have already.
But OS X will be running off the SSD.
True, but I'm happy with my fusion speed, and I think for my main activities the performance is on point in terms of SSD performance. A few subsecond improvement is not worth the increased amount of work to split it up and maintain two drives.
I may change my mind, but right now, I'm happy with the performance and a slight increase just won't by me much.
Then it sounds like for your usage there's just no need.
I am in favor of everyone being able to use the best machine for their specific use above all else.
I wanted to update this thread.
Due to a series of actions, and issues, I was facing the prospect of rebuilding/reinstalling OS X on my iMac. At this point, since I had a current cloned image of my system on an external drive I decided to break up the Fusion drive to see if that would work for me. As I stated earlier in this thread, I have waffled on this, wondering if its something I wanted to do or not.
The action of splitting up the fusion drive was dead simple, and using Carbon Copy Cloner, I was able to fairly easily put my data on the spinning drive and the OS, apps and home folder on SSD.
When the dust settled, I found I was facing only 25GB of free space on the SSD, and that's with only a tiny portion of my home folder on the SSD. I could not have my music, pictures, and documents, and download folder on the SSD, and even so my library folder is still sucking up 48GB of space - most of that is iPhone backups (I not only have my iPhone being backup on my machine, but also my two daughter's).
I'm not sure I want to live with the drives split up, given that I have so little free space
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As a side note, I wanted say how slow running OS X on a 5400 rpm drive via USB. Man that was painfully slow, and I don't mean using CCC to restore my data - just booting up was incredibly slow.
Due to a series of actions, and issues, I was facing the prospect of rebuilding/reinstalling OS X on my iMac. At this point, since I had a current cloned image of my system on an external drive I decided to break up the Fusion drive to see if that would work for me. As I stated earlier in this thread, I have waffled on this, wondering if its something I wanted to do or not.
The action of splitting up the fusion drive was dead simple, and using Carbon Copy Cloner, I was able to fairly easily put my data on the spinning drive and the OS, apps and home folder on SSD.
When the dust settled, I found I was facing only 25GB of free space on the SSD, and that's with only a tiny portion of my home folder on the SSD. I could not have my music, pictures, and documents, and download folder on the SSD, and even so my library folder is still sucking up 48GB of space - most of that is iPhone backups (I not only have my iPhone being backup on my machine, but also my two daughter's).
I'm not sure I want to live with the drives split up, given that I have so little free space
Did you move your home folder onto the spinning drive? I cannot find any other solution to get 60GB free, other then moving the home folder off the system drive.
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As a side note, I wanted say how slow running OS X on a 5400 rpm drive via USB. Man that was painfully slow, and I don't mean using CCC to restore my data - just booting up was incredibly slow.
That sounds high. Have you cleaned out the cache recently? I boot externally from a 256GB SSD and only use 55GB-60GB total. I don't have a lot of applications installed, but there are five or six programs from Adobe, Spotify, OpenOffice, three games at that are five or six GB. A few other miscellaneous applications. My Home folder is bare, aside from games and applications. I keep all documents, photos for Lightroom, and music on the the internal Fusion drive. I think you can move everything that is not an application off to the spinning drive to make room. Photos and documents don't need the speed, the applications that open them do.
The bottom line for me is that with Fusion Drive, 99% of the time the computer is writing data, it is going to the SSD. That, plus the time savings of not having to fiddle around with where to keep stuff, vastly outstrips the non-Fusion set up for me.
As I mentioned in another thread on this topic, I would just like for Apple to allow us to configure separately how big of an SSD goes into Fusion Drive. My current set up is with a 512GB ssd fused to a 1TB hard disk and that is perfect.
As I mentioned in another thread on this topic, I would just like for Apple to allow us to configure separately how big of an SSD goes into Fusion Drive. My current set up is with a 512GB ssd fused to a 1TB hard disk and that is perfect.