Read Errors with two clone programs only. Anyone else seeing this

Discussion in 'OS X Yosemite (10.10)' started by rachalmers, Jan 4, 2015.

  1. rachalmers macrumors member

    rachalmers

    Joined:
    Oct 21, 2012
    Location:
    UK
    #1
    I'm running 10.10.2 Beta. On purpose. And I'm using third party programs. However - I think the problem could be in Yosemite itself. Only the Nazi's on the Apple Developer forums can't get past the first line, so I can't get an intelligent response there

    Yosemite 10.10.2 Beta runs fine mostly so far. I love it.
    The thing I'm finding odd now though is that when I use either Carbon Copy Clone, or SuperDuper!, both programs report Read Errors.
    This has only begun to happen since coming up to 10.10.2

    DiskUtility and fsck do not report any errors.
    Apple Support tell me that if those two programs don't find any errors on the disk, then there aren't any physical errors.

    Carbon Copy Clone tells me in it's popup, that Read Errors can also be caused by things OTHER THAN disk defects. Software, firmware etc. So I'm thinking a lag in the Read/Write buffers maybe? Something like that.



    It's a Mac Mini,
    OSX Yosemite. 10.10.2 Beta.
    Model Name: Mac mini
    Model Identifier: Macmini6,2
    Processor Name: Intel Core i7
    Processor Speed: 2.3 GHz
    Number of Processors: 1
    Total Number of Cores: 4
    L2 Cache (per Core):256 KB
    L3 Cache:6 MB
    Memory:16 GB
    Boot ROM Version:MM61.0106.B03
    SMC Version (system):2.8f1


    Now,
    Carbon Copy Clone went through and finished the Cloning of the drive. Reporting 21 Read errors.

    SuperDuper! stops when trying to read certain files in the log directory.
    Code:
    SuperDuper![22277]: ***ERROR OCCURRED: SDCopy: Error copying /private/var/log/appfirewall.log to /Volumes/SuperDuper!/private/var/log/appfirewall.log of type 8 due to error 5: Input/output error
    If I exclude the whole log directory, it completes fine. Reading air writing with any other program from/to that directory does not cause errors. Just the Clone software.

    This is virtually a brand new system/drive, so I find it really unlikely that a drive is going to start failing when less than 12 months old. Possible, but improbable.

    My question is: Is anyone else showing similar errors with 10.10.2 Beta and cloning software. I have seen ONE person in the forums reported similar things, and they reverted to Mavericks, and the problem went away. I now can't find their post dam it. I don't want to revert anyway, I'd just like to pursue this idea that the R/W engine may be not absolutely stable in this release.
     
  2. maflynn Moderator

    maflynn

    Staff Member

    Joined:
    May 3, 2009
    Location:
    Boston
    #2
    Did you try using rsync to see if that also incurs errors. What if you used Finder to copy that directory to another directory or drive, just to see if that works. I'd also use cp in the terminal. My point is trying to see if its the two back up programs or your drive.

    To be honest, having 2 different programs report errors on your drive, sure does point to the storage having issues and not the OS.
     
  3. rachalmers thread starter macrumors member

    rachalmers

    Joined:
    Oct 21, 2012
    Location:
    UK
    #3


    Yes, this is probably true. However, I'm still looking into this problem, and with SMART technology, there are other things to consider that may ... help?

    So far, my research is finding that with SMART, when read/write block errors are found, the system will map out the bad blocks, and move the data to a new, clean block. BUT... only when the new data is Written. If Only further Reads are performed, nothing happens. Nothing is moved, and it keeps repeating the the Bad Read.
    So, locating the offending file - if possible - and Trashing it, and then emptying the trash so links are removed as well, then Restoring the offending file - writes it to disk, and in a new place, allows SMART to map out the bad block.

    Now this of course has a "gotcha"... if the file you want to remove and restore is a critical system file... you are in deep do do.... However, it appears to work for other files. This is why a full format/restore works, because bad blocks everywhere are being mapped out.

    It's not helping in my case though - as I do think the disk is ...failing. Not sure yet.
    This leaves another question : Do SSD "drives" suffer from 'bad block' R/W errors?
     
  4. Weaselboy Moderator

    Weaselboy

    Staff Member

    Joined:
    Jan 23, 2005
    Location:
    California
    #4
    Sort of... the data is stored in NAND cells and if they go bad the drives controller remaps that cell to another free area on the drive and marks that cell as bad.
     
  5. rigormortis, Jan 5, 2015
    Last edited: Jan 5, 2015

    rigormortis macrumors 68000

    rigormortis

    Joined:
    Jun 11, 2009
    #5
    every single hard disk made since 1993 is capable of correcting errors and moving them to different sectors automatically. all errors are automatically corrected without the operating system finding out.

    if you have an IBM PC from 1985 that uses MFM AND RLL controllers. like dumb disk controllers then you should follow rachalmers's advice. but i find that very hard to believe anyone out there is still using 20 and 80 meg drives like the seagate ST225 and the ST4096 from 1989

    once the operating system detects a bad sector the hard drive is considered shot. and you should get whatever data off of it, and have it replaced. case closed.

    all hard drives ship with bad sectors, and the hard disk comes with its own spare sectors, once the hard disk has run out of spare sectors, and the operating system finds out, it is considered SHOT

    bad sectors cannot be reliably marked bad by the operating system, because there is no longer a mechanism to LOW LEVEL FORMAT the drive. all you can do to a hard disk now is write zeros to the entire disk, you can no longer mark them bad permanently. if you do mark them bad and move them to good sectors with the operating system, it will just come back to haunt you when your hard disk finds more bad sectors

    every single hard drive made since 1993 was servo written by the factory with its own permanent bad sectors and a bank of spare sectors that is intended to last the lifetime of the hard disk

    the hard drive's error correction schemes are so reliable, that even people on the phone with applecare think the drive is shipped without any errors. which is not true

    you can check the drives smart sensor by clicking on the apple logo, click on about this mac, click on system report, and clicking on storage on the left. if it says 'unsupported' it means you have it in a usb enclosure. if its verified, the drive is presumed to be good and utilities can fix it. if the dive has failed or it is failing, no software utility and no attempts at formatting or wiping can save that drive, it has failed and it must be replaced.

    your warranty choices if the drive has failed ( or even if the operating system reports bad sectors )are
    take it back to apple to have the drive replaced if its under warranty
    take it back to apple to have the drive replaced if you have apple care
    give the serial # and results of the disk test to the drive manufacturer if you purchased the drive in a retail box
    if you buy a bare drive, in a antistatic bag, and no retail box, or if it was sold as a component , then typically you have no warranty

    i read SSD drives are under warranty regardless if they are in a static bag or a retail box, but not sure
     

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