Fusion vs SSD Regarding Mean Time Between Failure (MTBF)

Discussion in 'Mac mini' started by gcortes, Nov 13, 2012.

  1. macrumors member

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    Redwood City, California
    #1
    I'm trying to decide between a new Mac Mini with a fusion drive or one with the internal SSD and a external La Cie RAID 1. Is there information on the mean time between failure (MTBF) for the fusion drive and the internal 256GB SSD? I asked at the Apple store, but they only could say the SDD would last longer, but not by how much.

    Thanks for any help,
    Curt
     
  2. iamsen47, Nov 14, 2012
    Last edited: Nov 14, 2012

    macrumors regular

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    #2
    Considering Fusion has only just been released, there probably isn't enough data yet to produce any meaningful averages.
     
  3. thread starter macrumors member

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    #3
    I found this article on the comparison of HDD's and SSD's reliability. It's a year old, but it basically says that SSD's aren't significantly better than HDD's. Given that SSD's haven't been around that long, a longer history could change the picture.
     
  4. macrumors 68040

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    Dec 17, 2009
    #4
    As stated, "fusion" drives have only been out for a couple of weeks now, but a few items of note (at least how I see it):

    1. SSD's aren't any better or worse than Hard drives when it comes to failures. Flash memory will degrade over time, but their biggest failure point is actually their controller chips failing. Hard drives are mechanical and thus are prone to failure due to motors dying and/or locking up.
    2. Technically, just like any RAID 0 setup or Drive Spanning (it's really more of a hybrid Drive Spanning), it would be more prone to failure than an SSD or hard drive by themselves only because now you have two drives that are each prone to failure of X rate and you have combined them into 1 "drive" thus increasing the failure rate. As independent disks, you only lose what's on one drive.

    With all that said, in the end you need a good backup solution regardless if you go Fusion or independent disks, you need a good back up solution (i.e. Time Machine) in case of a failure.
     
  5. macrumors 603

    philipma1957

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    #5
    this

    also I would say do a clone a week onto an external drive and the tm suggested above.
     
  6. macrumors P6

    Weaselboy

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    #6
    I agree and this is what concerns me somewhat about Fusion. If either drive fails, your system is dead. So we have doubled the odds of a drive failure stopping a system.

    Not that concerned about data loss as we still have the same backups as before.
     
  7. macrumors 68040

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    #7
    It's the same failure rate as people who have used RAID 0 and/or Hard Drive Spanning for all these years. However, I've never been a fan of either Hard drive Spanning or RAID 0 either and rarely recommend them due to the increase in failure rate.

    With that all said, Fusion is something I am considering for my wife because she just can't seem to get that her SSD is for her OS and Apps and her HD is for her photos, videos, music, etc. in her Macbook Pro.... I'm willing to take a chance on Fusion to alleviate the day to day headaches!

    Backups are always necessary!!!
     
  8. macrumors regular

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    Toronto
    #8
    How do you get fusion drive? when i order mac mini from apple website, it doesnt have the option?
     
  9. Weaselboy, Nov 14, 2012
    Last edited: Nov 14, 2012

    macrumors P6

    Weaselboy

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    #9
    It looks like you have to bump up to the i7 CPU model for that option to appear.
     
  10. macrumors 68040

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    #10
    You can also "roll your own", by adding your own SSD to your mini and then using the tutorials available online. If you want Apple's solution, then yes you need to go to the Mid-Mini.
     
  11. thread starter macrumors member

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    #11
    I just wrote a long reply and then lost it when my session timed out before I submitted it. I keep forgetting MacRumors does that.

    I use Time Machine with an IOSafe, which is a USB attached drive in a waterproof and fireproof enclosure so I have data backup covered. My goal is to reduce recovery time the case of a failure. If I went with the 256TB SSD, I would pair it with the LaCie 2Big in a RAID 1 configuration. If one of the drives in the array failed, I would still be operational while I replaced the bad drive.

    Good point about the two points of failure with the Fusion drive. Since, as I understand it, all the data on the SSD is also on the HDD, would the unit still be operational if the SSD failed?
     
  12. macrumors P6

    Weaselboy

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    #12
    Based on reviews/tests I have read, I don't believe that is the case. If either drive dies, the system is toes up.
     
  13. macrumors 68040

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    Dec 17, 2009
    #13
    No. This is incorrect. Many believed that Apple was utilizing Intel's version of the fusion drive which does keep a copy of the OS on the hard drive initially, but Apple instead chose to not use Intel's version (I forget what it's called and am too lazy to look it up). For Intel's version you get only what is available on the mechanical drive as your total storage since the OS is stored on both the SSD and the mechanical drive. Apple's version (fusion) does not store what is on the SSD on the mechanical drive that is why you have a total storage space of the SSD + the hard drive (so the 3TB fusion is really 3.1TB).

    Edit: Intel's "version" is called Smart Response Technology (SRT)
     
  14. macrumors regular

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    Mar 14, 2011
    #14
    This is incorrect. Data is always written to the SSD first, and infrequently used data is then demoted down to the HDD for long-term storage. As HDD data is accessed more frequently, the OS may promote it back to the SSD for faster access. At no time is the data ever on both drives, so the discussion about the dual failure points is pretty relevant. You will still need a solid backup plan.
     
  15. macrumors G5

    gnasher729

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    Nov 25, 2005
    #15
    It's difficult to say. Any drive doesn't last a fixed time, it depends on the use. The HD part of the Fusion drive will benefit from all the small files that need lots of head movement not being there. And the SSD drive will benefit from large files not being there. But then the drive is smaller, so each block is used more often than on a big drive. But then 128 + 1TB is so much bigger than 256 GB and so much cheaper than 768 GB SSD...

    In the end, the truth is that your drive _will_ die on day. Nothing changes that. And then you need a backup.
     
  16. macrumors member

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    #16
    I want a 256TB SSD for Christmas. Are you listening Santa? :D
     
  17. macrumors 65816

    dasx

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    #17
    A Fusion Drive isn't anything more than an SSD and a HDD, so the possibility of a hardware failure if the same as one of those failing.

    It then has some software and stuff making it work as the actual 'Fussion Drive', but a software failure is easily fixable (in theory).
     
  18. macrumors P6

    dukebound85

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    #18
    But the odds increase

    Say that, for the sake of argument, that the reliability of both the hdd and ssd is 90%

    If you combine them into one drive (ie a raid 0 like fusion), the reliability is not 90%. Instead, it is .9*.9 = 81%.
     
  19. macrumors 65816

    dasx

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    #19
    Yes but we're probably talking about reliabilities of 99.9999% during warranty or so. My point being The difference isn't noticeable.

    What I tried to point out is that these disks aren't gonna probably be much more reliable or on the other way much more prone to failure as they're just a well known HDD + a regular SSD.
     
  20. macrumors 68020

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    #20
    The Fusion drive is for people who don't know how to, or don't like to, manage their files, i.e., move files like photos/videos/songs/etc. to a "data drive."

    If you're okay with managing your files, then just get the cheapest Mini possible and put whatever drives in it you want. It's easy to swap drives in a Mini and you can get drives much cheaper than what Apple sells them for.

    Personally I will be buying the mid-Mini and attaching an SSD via USB3 and booting off of that. Easy and fast.
     
  21. macrumors 65816

    phoenixsan

    Joined:
    Oct 19, 2012
    #21
    I would say....

    MTBF for Samsung 830 it is around 1,500,000 hours and for Crucial 1,000,000 hours, if my memory works. No word about Fusion because benchmark/data are scarce based in how new is the technology in current Macs.

    :):apple:
     
  22. macrumors 603

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    #22
  23. macrumors 68040

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    #23
    The recommendation in this thread is to use Time Machine and do a Clone of your fusion drive roughly once a week. If the Fusion drive fails, then you boot from your clone drive. Once the fusion drive is back up, then you can use Internet recovery, load the OS and migrate the data back from Time Machine.... The whole point of Fusion is for those who have limited understanding of SSD's and HD's. Frankly, most users of Fusion probably don't even care that much and if they had a catastrophic failure, Internet Recovery and Time Machine would be more than enough for them (probably wouldn't even know how to fix a drive failure themselves anyway).
     
  24. thread starter macrumors member

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    #24
    Actually, I'm going to go with an internal 256GB SDD for OS and programs and a 2TB external RAID 1 for data. With that much space, I could create a partition to contain a clone of the SSD. If the SSD fails I could boot from the clone. If one of the array drives fails, I'm operational while I wait for a new one. The other advantage is that the external RAID can still be used when I upgrade the Mac Mini in the future. I could also replace the array drives with larger ones if necessary. Come the day when we have 2TB SSD's, I'll just get two of them in my Mac Mini, which probably be a micro by then.
     
  25. macrumors 65816

    Joined:
    Jul 26, 2011
    #25
    I learned the hard way that typing a lot of text into a web browser is risky. And it isn't just session time-outs that can erase a lot of work. These days I copy the text as I write or input text into a word processing program and then transfer it to a web browser.

    As far as drive failure goes... I had a brand new Toshiba drive die within two hours after I had a repair shop replace a dead drive in an iBook. The shop fixed it for free but I had to pay for shipping and wait another week or so for the iBook to be returned.

    Backups? At least two on the premises and another via CrashPlan...
     

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