Time Machine volume on NAS corrupt once a month

Discussion in 'Mac Basics and Help' started by oreggero, May 31, 2016.


Does the described problem also occur when backing up to a Time Capsule?

Poll closed Jun 7, 2016.
  1. Yes

  2. No

  1. oreggero macrumors newbie

    May 27, 2016
    Hi community!

    I own a WD MyCloud EX2 which I use for Time Machine Backups. Unfortunately, there is an issue with backing up to NASs in Time Machine and I keep getting an error message which says something like: "Time Machine completed a verification of your backups. To improve reliability, Time Machine must create a new backup for you." and that it needs to delete old backups to do so.
    This happens about once in a month or two, since I have the MyCloud NAS.

    Basically, it renders Time Machine useless in my opinion, since I often need to recover files that I deleted more than 1 month ago.
    After searching the internet for information regarding my problem, I found out that this seems to be a very common problem when backing up to NAS. I found this tutorial for repairing the .sparsebundle http://www.garth.org/archives/2011,...ine-sparsebundle-nas-based-backup-errors.html and tried it and also the shell script that is linked in the comments below the tutorial, but both did not work for me. (And even if it did, it still would be annoying, having to repair the backup every month which takes around 6 hours.)

    So, my question is, if anyone around here who owns a Time Capsule ran into the same problem, or if Time Capsules are not affected by this misbehavior?
    I am considering buying one to replace my WD device, but would only want do so if Time Machine would then work without needing to delete all backups once a month.
  2. kucharsk macrumors regular

    May 31, 2016
    I've never seen that occur with my Time Capsule.
  3. chabig macrumors 603

    Sep 6, 2002
    This doesn't happen with Time Capsules. I suspect it has something to do with WD.
  4. Mr_Brightside_@ macrumors 68030


    Sep 23, 2005
  5. patrickhb113 macrumors newbie

    Nov 1, 2014
    Has happened to me twice since buying WD Mycloud Mirror.
  6. kohlson macrumors 68000

    Apr 23, 2010
    I was using an older ReadyNAS Duo for Time Machine, and after a few rounds of the behavior you describe, I gave up and bought a Time Capsule. Rock solid since then, I've also attached a 4TB WD to the Time Capsule, and that's been solid, too. Imho, backups are supposed to be reliable and transparent, which is true (for me) on TC, and false for the TM on ReadyNAS Duo.
  7. Belgique macrumors member


    May 6, 2016
    Ocala, Floridah
    I have a Time Cap and have never, ever sucessfully restored anything.
  8. PilotWoo macrumors regular

    Jul 14, 2006
    I bought a single drive WD MyCloud for this express purpose a year or so ago. Had no end of problems with the issue you describe. Sold it on eBay and bought a Mac Mini. Now use OSX Server to host time machine backups. I have had ZERO problems with it in the last year.

    My advice would be to ditch the MyCloud if you can, its not fit for this purpose.
  9. grahamperrin macrumors 601


    Jun 8, 2007
    Any number of things might cause an HFS Plus file system inconsistency.

    Time Capsule aside

    If you –
    1. use ZFS-based storage;
    2. occasionally take a snapshot (ideally when the client is not backing up); and
    3. regularly scrub the storage system
    – then regaining a consistent HFS Plus file system is as simple as rolling back to a ZFS snapshot of a good point in time.

    Goodness here with FreeNAS.
  10. arggg14 macrumors 6502a

    Dec 30, 2014
    I have a MyCloud Ex4100, but I haven't had any of the issues you're describing.
  11. maflynn Moderator


    Staff Member

    May 3, 2009
    I noticed something along these lines with my Qnap NAS back in the day. I've largely stopped using the NAS for a number of reasons, but one of which was consistently incurring TM errors.

    I'm not using a Drobo Mini DAS and I've not had any errors, before the NAS and DAS, I did use a TC, and that too was rock solid, but wicked slow. I opted for the NAS, for more flexibility and it was a bit faster, but I finally settled on the DAS that gives me both speed and flexibility
  12. Le Big Mac macrumors 68030

    Le Big Mac

    Jan 7, 2003
    Washington, DC
    I get this message sometimes with an HD attached to my apple TC via USB.
  13. HvLee macrumors member


    Aug 6, 2014
    The Netherlands
    Using 2 Synology's as TC, never happend to me before. (3 macs)
  14. AppleNewton macrumors 68000


    Apr 3, 2007
    1 Finite Place
    Generally the error occurs when an issue with network connections using back ups that way.

    Refer to these:



    But I have an AirPort Time Capsule that back ups everything wirelessly and I have an additional back-up USB disk connected that does a secondary back-up as well for the past 2.5 years without any issues.
  15. grahamperrin macrumors 601


    Jun 8, 2007
    With a suitably robust NAS, the OS X client should eventually recover, without user intervention, from ungraceful interruptions to network service; and from ungraceful interruptions to file service. For the past few months I have tested Mavericks with FreeNAS, no problems from such interruptions.
  16. Moohooya macrumors newbie

    Jul 11, 2010
    I used to get this constantly using my QNAP NAS. After several years it finally went away, if I recall correctly after a firmware update by QNAP.

    If I were to build a new backup system I would go TC and forget the NAS. It seemed cool at the time but I must have spent 100 hours over the years researching the issue, trying new ideas which never worked and creating new backups.

    TC users seem unaffected by these issues
  17. gnasher729 macrumors P6


    Nov 25, 2005
    There are NAS's where this happens all the time. Had one at a previous job; bought an external hard drive for £30 that did the job just fine without all the trouble. With the NAS, every three or four weeks it had to make a complete backup, which means half of the value of Time Machine (having really old backups available) was gone. And of course your computer might die during the time between the last backup and the new backup and then you are stuck.
  18. smirk macrumors 6502a


    Jul 18, 2002
    Orange County, CA
    I back up via Time Machine to my own Linux server running Netatalk, which is the product that all NAS units use to provide Time Machine capabilities, as far as I know. Generally, it works well, but I have observed that it will fail in the manner you described if my Mac goes to sleep or shuts down in the middle of a backup.

    Once I disabled Sleep and started checking for in-process backups before shutting down, my Time Machine corruption ceased. I've been backing up in this manner for probably 4-5 years now, and so far it has been working well. However, I will say that I tend to think of Time Machine as convenient but somewhat fragile, so I also do full backups periodically with Carbon Copy Cloner.
  19. grahamperrin macrumors 601


    Jun 8, 2007
    Which version of the OS?

    Re http://forums.macrumors.com/posts/22974859 above I took an aggressive approach to testing FreeNAS, which uses Netatalk. No corruption.
  20. smirk macrumors 6502a


    Jul 18, 2002
    Orange County, CA
    Netatalk was running on Xubuntu 12 and 13, and OS X on Mavericks, Yosemite, and El Capitan.

    I don't really know what's going on here that makes it fail, but if I had to guess, I'd say that FreeNAS is tuned such that it keeps Time Machine sessions open longer, so when the Mac wakes back up it just continues where it left off. Or something like that.

    Also, the TM corruption doesn't happen every time for me. Sometimes I shut down during a backup and it's fine. But sometimes it isn't.
  21. grahamperrin macrumors 601


    Jun 8, 2007
    I'm not aware of any tuning along those lines. https://sourceforge.net/p/netatalk/bugs/382/ was closed in 2012; it's amongst the resources that I found whilst working on an enhancment to the FreeNAS guide.
  22. smirk macrumors 6502a


    Jul 18, 2002
    Orange County, CA
    That's interesting. I (and, obviously, others) do experience corruption from time to time. I'm not familiar with FreeNAS, but could ZFS be doing something that ext4 isn't?
  23. grahamperrin macrumors 601


    Jun 8, 2007
    Yes, but I'm not familiar with ext4 so I can't say whether the differences are relevant in the Time Machine server context.
  24. rworne macrumors 6502a


    Jul 23, 2002
    Los Angeles
    I have not had that pleasure with my TC, but ever since El Capitan, I've been getting the same error about starting a new backup. Pretty much every time it does a monthly verification. Troubleshooting it, I discovered:

    1. A failing disk in the TC, replaced the 3TB drive with a new 4TB drive. Still get errors.
    2. Went from WiFi to wired Ethernet. It's better, but still failed.
    3. My other Mac, a rMBP, has the same issue.

    Now there is another Mac in the house that is connected to a LaCie via the lightning port. That sucker has been going for the better part of 2 years with no errors.

    So now I still back up my iMac to the TC, and to another drive connected to the lightning port that I just purchased. My TC on this mac only goes back to May 22, 2016. I'm expecting yet another verification failure in a couple more weeks. I hope the external drive fares better.
  25. shaunp macrumors 68000

    Nov 5, 2010
    I had this years ago on a QNAP NAS when Lion was released but from Mountain Lion onwards it was fine. Never noticed a problem since then on either QNAP or Synology NAS's. Raise a support call with WD and if you don't get any joy then use Carbon Copy Cloner and just backup using this to the NAS instead as it's a lot cheaper than buying a new NAS.

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