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Luke Christian Level 1 Level 1 (25 points)

With the falling prices of SSDs, I am fascinated by the prospect of adding one to my Late-2012 quad-core i7 Mac mini and set it up as a single Fusion Drive volume with the existing 1TB HDD.

 

The clunky 5,400rpm HDD that it came with is laboriously slow and the opportuity to add a 256GB SSD (probably a Sandisk?), for a lot less than the incremental price hike of having specified a 128GB Fusion Drive in the first place, seems very tempting. Better still, it was mentioned, in another thread, that Disk Utility in later Mac Minis automatically set-up two installed drives as a single Fusion Drive volume, so I would not even have to delve into the dark arts of the Terminal to set it up, just pick-up a disk doubler kit from iFixit or OWC, drop in the SSD, load OS 10.9 onto the SSD, boot into Disk Utilities, select 'Repair Disk' then go and make a cup of tea!

 

Even though I might have to forfeit my remaining 6 months of Applecare, it seems like a compelling way to vastly improve my Mac mini's disappointingly sluggish performance. I always back-up to Time Machine so am not overly concerned about doubling the risk of data loss with a Fusion set-up.

 

It all seems too alluring... am I missing something?

 

Can someone temper my enthusiasm before I bite off more than I can chew with a perfectly good 6-month-old Mac mini?


Mac mini, OS X Mavericks (10.9), rMBP, 2x 24" LG monitors.
  • Allan Eckert Level 8 Level 8 (47,420 points)

    I created one in my Mac Pro and it really improved the performance for me

     

    For some insight on how to do it here is the site I used to make mine.

     

    http://blog.macsales.com/15617-creating-your-own-fusion-drive

     

    It does include directions for the Mac Mini

     

    Good luck

     

    I created mine with a 120 GB Accelsior PCIe SSD card and a 1 TB disk. I was able to move the vast majority of my files in addition to my system and applications to the Fusion Drive.

     

    Allan

  • Luke Christian Level 1 Level 1 (25 points)

    That is helpful, thanks.

     

    I would, ideally, like to install the new disk without using Terminal commands. Partly because it worries me that I might make a mistake and get in a muddle and partly because my Mac mini is still under Applecare and I am rather hoping that, were something unrelated to fail during the warranty period, I could hastily return it to its original state and not all would be lost. I am concerned that if I meddle with the Terminal settings the Genii would give me a knowing smile and show me the door.

     

    I also wonder whether letting the Apple OS X do its stuff, rather than my intervening with the Terminal, might be a purer way ensure that I would not be storing-up potential conflects later. 

     

    One thing that I am also trying to figure-out is how best to enable TRIM settings on the SSD. Have you done so with yours?

  • Allan Eckert Level 8 Level 8 (47,420 points)

    As far as I know the only way to create a Fusion Drive is by command line.

     

    I have not  tried to do anything with Trim at this time.

     

    Allan

  • Luke Christian Level 1 Level 1 (25 points)

    I have read that enabling TRIM significantly benefits long-term performance and reliability.

     

    Apparently, OS X only switches it on automatically for Apple-supplied SSDs, but you can persuade it to recognise a non-Apple-branded SSD.

     

    You can read more about it here:

    http://www.mactrast.com/2011/07/how-to-enable-trim-support-for-all-ssds-in-os-x- lion/

    https://discussions.apple.com/message/22535463#22535463

    http://forums.macrumors.com/showthread.php?t=1409151&page=4


  • keg55 Level 5 Level 5 (6,985 points)

    You don't need to use Terminal commands with OS X Mountain Lion 10.8.2 and above (which includes OS X Mavericks). You can create your Fusion drive by restarting into the Recovery HD (Command+R). Then launch Disk Utility. You will see both drives marked in RED lettering and a popup will display giving you an option IGNORE or FIX. Clicking FIX will erase both drives and automatically create a Fusion drive. So, do a full system back up before creating a Fusion drive.

     

    In case you want to use the SSD and HDD separately, know that in Disk Utility from the Recovery HD in OS X Mountain Lion there's a bug with the IGNORE/FIX buttons. The IGNORE will do nothing and won't let you individually manage each drive. You would have to use Terminal (diskutil) to manage them. In OS X Mavericks, that bug has been fixed and clicking IGNORE will change the RED lettering to black and let you manage each drive separately.

     

    TRIM aids in the reduction of write amplification and some improved performance. A 3rd party free app called Trim Enabler will enable OS X's TRIM feature on 3rd party SSD drives.

     

    This produces three key benefits: 

    1. Lower write amplification. Less data is re-written and more free space is available during GC (more space to write equals fewer writes needed);
    2. Higher throughput. With the TRIM command, there is less data to move during GC and the drive runs faster. Throughput is bottlenecked at the flash an SSD is only as fast as it can write to the flash memory. During the time it is doing GC, the drive has to stop some of the data transfer from the host while it moves data around. This is why it’s beneficial for the SSD to know which data is invalid so it doesn’t have to be moved during GC.
    3. Improved endurance, because the drive is writing less to the flash by not rewriting invalid data

     

    I had a Fusion drive in my late-2012 Mac Mini (120GB SSD, 500GB HDD) and there was a definite performance improvement. I think it booted up in ~16 seconds compared to ~ 30 seconds without it and apps launched much faster. I've since "defused" the drives and have separate drives. Just a preference for me, but I didn't have any issues with a Fusion drive and I enjoyed the ease of file management which was done for me by Core Storage. I didn't enable TRIM on my 120GB SSD since I rarely do any deleting of files. Most files are deleted off my HDD which is used for LAN file storage. So the built-in Garbage Collection on my SSD is good enough.

  • Luke Christian Level 1 Level 1 (25 points)

    That is very helpful keg55, thank you!

     

    It would make sense for the OS X recovery partition to be on the SSD, rather than remaining on the existing HDD, so I guess the appropriate procedure would be to re-download and install OS X onto the SSD before installing it into the Mac. I could then option-boot into the SSD, erase the HDD using Disk Utility, reboot into the recovery partition (there, now, only being one - on the SSD) and 'repair' the disks into one Fusion Drive before restoring everything from Time Machine.

     

    Did I miss anything? Many thanks again for your help!

  • keg55 Level 5 Level 5 (6,985 points)

    It's actually easier than what you wrote.

     

    Download the OS X Recovery Disk Assistant from Apple (it also works with Mavericks) and use a 4GB thumb drive to create a Recovery HD on that thumb drive. Do a full system back up.

     

    Then, all you need to do after you install your SSD into the Mini is:

    • Plug in your thumb drive
    • Restart and press the Option/Alt key and select your thumb drive so it boots into the Recovery HD
    • Launch Disk Utility (you'll see the RED letting for each drive)
    • Click on your SSD which will bring up the IGNORE/FIX screen
    • Click on FIX which will create your Fusion drive
    • Back out of Disk Utility -- back to the OS X Utilities Menu and select Reintall OS X

     

    Mavericks will install onto your SSD and as you reinstall or migrate apps and your data, Core Storage will keep writing to your SSD until is fills up then "spill" over to the HDD. The Recovery HD will be on your Fusion drive after you install OS X. But you won't see it in the Startup Manager if you ever restart using the Option/Alt key. You WILL be able to use Command+R though anytime you need to access it. This is just how it is with a Fusion drive.

  • LexSchellings Level 5 Level 5 (6,860 points)

    Hello Alan, I sense a hesitation about the Trim command. I have a number of years experience with that on many different SSD's. Here is what my idea is at the moment: It does start the erase of deleted files on the SSD by a trim command form the OS. If there is no trim command as for SSDs that are not installed by Apple, then this erasing is started by the garbage collection in the SSD controller. You know that already.

    There are different controllers used by SSD manufacturers Marvell and Sandforce as the most known. Marvell has (amongst other plusses) a very efficient Garbage Collection, the others are less efficient. But all the latest variants do not have a serious need anymore for trim. In my latest SSDs with Marvell controller (e.g.Crucial M500) I do not install it. I still hesitate in the Sandforce case (Samsung EVO, renamed): Even after a year of daily use of both, I see no change in the write speeds.

    My experiences with TrimEnabler is not very good, I use Chameleon when necessary. Both have the disadvantage that after having done twice, the backward return to before is not possible unless you first enter the kext file manually. Doing it manually yourself as Grant Pannel in the beginning SSD period posted is not very adviseable anymore. Both softwares are not to be trusted according to Linc Davis, although that does not mean that they malperform but because you can not check the coding yourself. FYI the TrimEnabler is just terminal commands, while Chameleon is in C.

    Thank you for letting me explain, I realise you had no choice

    Lex

  • Allan Eckert Level 8 Level 8 (47,420 points)

    Thanks for the explanation, Lex.

     

    On the Fusion Drive that I made with an Accelsior PCIe SSD card, I have been using it now for the last six months since I configured it. I just tested it again for read/write speed and recieved that same numbers I had when I configured it. I will continue to wait on Trim.

     

    Allan

  • LexSchellings Level 5 Level 5 (6,860 points)

    Good thinking; as an afterthought: even when you see a slowdown in the write speed it is not more wear without trim than with trim: just do a "erase free space" once and install the Trim if you want to.

    Lex

  • Luke Christian Level 1 Level 1 (25 points)

    Just to be clear, are you impying that if I buy a Marvell-controlled SSD (SanDisk Ultra Plus or Crucial M500) I can probably manage without TRIM (at least until my Applecare runs out!).

     

    I have, in any case, been disuaded from choosing the Sandforce-controlled Samsung 840 Evo because of the poor theoretical durability of the TLC, as opposed to MLC, technology (http://www.anandtech.com/show/7173/samsung-ssd-840-evo-review-120gb-250gb-500gb- 750gb-1tb-models-tested).

     

  • LexSchellings Level 5 Level 5 (6,860 points)

    I am implying that in my opinion it does not do much for when you install the trim command for any new SSD.

    The disadvantages of putting in the trim command also is that every time there is an update of the OS there is a chance that the kext file is replaced and you have to do it again, without knowing up front that the part you replace in that kext file is changed or not!

    In the past I looked into that as far as possible, but now I don't see the advantage (only theoretical now) any more.

    Besides that I have my preferences for the Marvell controller (it is much more flexible in taking firmware updates for example).

    One of the "funny" things is that you should not do the speed tests too often, because that are a lot of writes to measure and it is the writes that wear out the SSD. But in general I estimate the lifetime of a modern SSD as much longer than the HD.

    Lex

  • Luke Christian Level 1 Level 1 (25 points)

     


    keg55 wrote:

     

    It's actually easier than what you wrote.

     

    Download the OS X Recovery Disk Assistant from Apple (it also works with Mavericks) and use a 4GB thumb drive to create a Recovery HD on that thumb drive. Do a full system back up.

     

    Then, all you need to do after you install your SSD into the Mini is:

    • Plug in your thumb drive
    • Restart and press the Option/Alt key and select your thumb drive so it boots into the Recovery HD
    • Launch Disk Utility (you'll see the RED letting for each drive)
    • Click on your SSD which will bring up the IGNORE/FIX screen
    • Click on FIX which will create your Fusion drive
    • Back out of Disk Utility -- back to the OS X Utilities Menu and select Reintall OS X

     

    Mavericks will install onto your SSD and as you reinstall or migrate apps and your data, Core Storage will keep writing to your SSD until is fills up then "spill" over to the HDD. The Recovery HD will be on your Fusion drive after you install OS X. But you won't see it in the Startup Manager if you ever restart using the Option/Alt key. You WILL be able to use Command+R though anytime you need to access it. This is just how it is with a Fusion drive.

     

    Fantastic advice thank you!

     

    I have just installed a Sandisk Ultra Plus 256GB using an iFixit Mac mini dual drive kit (just $30 in the USA) and the OWC video guide. It was amazingly straightforward.

     

    I followed the 6-point instructions from keg55 and, sure-enough, within seconds, it had set itself up as a single volume Fusion Drive. I am now just waiting for Mavericks to reinstall before migrating my data back from Time Machine.

     

    Seriously, no one with a late 2012 Mac mini, and a regular HDD, should hestitate. Provided you are reasonably handy with a screwdriver and can follow an instruction video, for the price of upgrading the RAM you can have a fully-fledged, Apple-created fusion drive!

  • keg55 Level 5 Level 5 (6,985 points)

    Glad to see things are going smooth for you and your Fusion drive.

     

    Just in case you develop issues trying to install OS X with your Sandisk SSD or have Disk Utility errors show up or issues trying to boot to your Fusion Drive, be aware that the iFixit.com SATA cable may not be compatible with your SSD assuming you mounted your SSD in the upper drive bay bracket. I had an Intel 520 Series SSD in that upper bay and never had an issue. I then purchased a Samsung 840 Pro SSD and had issues trying to install OS X or booting to the SSD. Disk Utility kept telling me there were errors and could not repair the disk. I read in the iFixit forum of others having this type of issue and the solution was to use the bottom bay (closest to the WiFi antenna grate) for my SSD and the upper bay for my HDD. This totally fixed the issues I had.

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