Inquiry about if the HDD fails in Fusion drive

Discussion in 'iMac' started by ThirteenXIII, Nov 12, 2012.

  1. ThirteenXIII macrumors 6502a

    Mar 8, 2008
    Since the data is tiered and spread from SSD to HDD as needed and its not like-for-like RAID but whena drive fails in this set-up do you essentially have to start from scratch like if a raid 0 build fails?
  2. dearlaserworks macrumors regular

    Apr 28, 2012
    Eastern Shore, USA
    Yes, replace failed drive, then restore from backup.
  3. wessew macrumors member

    Feb 4, 2010
    I would recommend having two backups. Also, it is not clear which software you use to run a restore. It is presumably not the software you use to create the backup?! Finally, there is the question as to whether it makes a difference which drive fails?
  4. dearlaserworks macrumors regular

    Apr 28, 2012
    Eastern Shore, USA
    Disk Utility to format the drives, then full restore with whatever tool was used to back up, e.g. Time Machine. The two physical drives appear as one volume to your backup software. If either drive fails, you'll need to perform a full restore of the backed up Fusion volume. Optimization of files between SSD and HDD will start from scratch, learning from your usage patterns after the restore.
  5. ThirteenXIII thread starter macrumors 6502a

    Mar 8, 2008
    actually i guess i missed the initial question iw as going to originally ask.

    The data on the failed mechanical HDD is that going to be recoverable? like if you were to hook it upt o an external is that data retrievable in the way it was "tiered" with the other SSD?

    or similar to a RAID-0 all is gone?

    which is interesting, if the hdd fails can the system still boot just on the SSD?
  6. Fishrrman macrumors P6


    Feb 20, 2009
    I'd like to pose some questions re the fusion drive concept that no one seems to be talking about yet.

    What happens when the fusion drive fails?
    What pathways to recovery will an "ordinary" (non-techie) user have?

    Since it was announced, there have been raves about how fast the fusion drive is, how "transparent" it is to the user -- and essentially nothing about what to do when it breaks.

    I sense that with fusion, Apple is trying to "dumb down" multiple disk management, in way not unlike Time Machine was intended to dumb down backup.

    With Time Machine, the end user doesn't have to do anything except connect a backup drive and "turn on the switch" -- backup becomes so easy! EXCEPT -- sometimes the user's drive fails, and they suddenly discover they've lost the ability to boot (we see postings to that effect right here). Or, they get booted, connect their TM backup and -- can't access it, it won't open, etc. (we see postings like that right here).

    With fusion, what happens in the case of a drive failure, either the SSD or HDD? Obviously, the computer isn't going to boot from the F-drive. The user may or may not be able to access the recovery partition, but even if he does, what kind of options will he have? If one drive is kaput, the F-drive won't work. Neither of them, unless the "fusion" is "broken" and the drives are un-fused. Will there be quick-n-easy software that can do this? Or will non-techie end-users be forced into the Terminal app? Will it become impossible to "un-fuse" a failed F-drive?

    At least with two "independent" drives, in the event of one drive's failure or directory corruption, the other drive will probably show up on the desktop. In that case, the user could install a basic system, and get going again.

    Actually, with both an SSD and a HDD, the best course of action is to partition the HDD, and create at least one "alternate boot partition" with an operational OS and some apps on it. Modern drives are large enough in capacity so that this is easy. There is NOTHING that can sub for an alternate boot source in a moment of extreme need. Not even the recovery partition can match that.

    Apple's fusion drive looks attractive for the masses, at the moment.
    But I see problems with it down the line...

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