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Yosemite and Time Machine

Since upgrading to Yosemite, Time machine doesn't work properly. It stops saying there's not enough space in my Time Capsule (needs 700 GB, I have only 600 GB).


I have a 2 TB Time capsule, 1,3 TB used with my previous backups. It seems to me that with Yosemite, Time Machine doesn't recognize my previous backups and is trying to perform a new one with the free space left on my disk.


I tried different solutions to no avail (restart the Time Capsule, erase stuff, check things I don't need to backup in Time Machine's Options, etc...).


I ended up erasing the disk entirely but Time Machine showed me the same message again. I erased it again and now it's making a full new backup, and for the moment it seems to work (10 hours to go. Anything can happen. Cross my fingers).


Also, during the first failed backup, I lost my wifi signal. I performed a network checkup an I had to restart my Time Capsule to make it work.


Everything worked fine with previous OS. Is it a Yosemite's bug?


Juan

iMac, Mac OS X (10.7.1)

Posted on Oct 24, 2014 8:03 AM

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Question marked as Best reply

Posted on Oct 27, 2014 10:37 AM

In summary - IMHO at least one BUG - in Yosemite the space calculations for Time Machine don't always give the right answer, so TM may delete backups it doesn't need to or erroneously report there isn't enough space.


If you look at the console log you'll see that first thing TM does is calculate how much space it MAY need. In Yosemite this is sometimes way off, by orders of magnitude. E.g a couple of days ago TM stated that it needed hundreds of GB to backup my rig, in the end it used tens of MB.


Now, if the (incorrect) calculation is more than the current free space it will start deleting backups until there is sufficient space. However, it doesn't delete the latest backup so you can end up with the size of that plus the incorrect calculation being larger than the size of the target disk. In this case you get the message about there not being enough space.


With my external drives, I always get the wrong answer being calculated when TM runs following a mount of a drive that was dismounted the last time TM ran.

24 replies

Mar 2, 2015 7:12 PM in response to Duncan Baillie

I was having serious problems using Time Machine when I updated to Yosemite for about 6 months. Then an update, that didn't even list Time Machine as a repair, fixed it. I am guessing that most people with TM problems, received this update, and it repaired there problem as well, because discussion seemed to stop after it was sent out. Still if an update fixed it, then it must have been, not as rare a problem, as apple said it was. Again although this update, didn't have 'anything,' listed about time machine, it fixed the TM problem I was facing. The major thing that that Yosemite update actually mentioned was WiFi. How this update mysteriously fixed my TM problem, is completely beyond me. Perhaps the update was never sent to you. I really hate to offer this as a solution, but perhaps you could take it to an apple store. They should probably know what the problem is. When they fix it, demand that they completely explain to you why your machine had problems using Time Machine.


I've never used Time Machine editor, but thank you for pointing out this application too me. My backup drive only has about a 1 TB of room, and quickly gets full. That app looks handy, but I don't see how it could fix a Time Machine problem, except by possibly creating more space in your back up drive. Unfortunately I don't think that not having space is your problem. TM should just automatically just ask you, if you would like to overwrite your old backups, hen it gets full. I will look more into its safety of use, but cutting down some on the frequency of backups, might come in handy. This would increase to amount of time my backups can go back to, potentially by a lot.


I really hope that someone here, can still offer you some assistance ...

Mar 8, 2015 5:43 AM in response to greenmind

Greenmind, thanks for coming back to me. I am up-to-date with my patches but I think my specific case is not quite the same as the one in this thread. The problem I have is when I use a second disk, which I plug in locally every weekend to make a second backup. During the week I backup over my LAN to a QNAP. Recently, after the weekend backup to the local disk is done, and I turn it off, Time Machine asks me to create a new full backup on the QNAP.


I've tried repairing the sparsebundle with disk util and fsck does not report any issues. Maybe I have hit a filesystem limit as some threads suggest. I think I'll just have to swallow another full backup and try to work out a process that lets me use two disks.


Very annoying of course because not only did it used to work fine, it has also destroyed my backup history. Another nail in the coffin of Apple as far as I am concerned; the operating system has turned into bloatware, just so complex. I hate to say it but Centos 7 is looking like a very nice desktop solution...

Aug 20, 2015 8:09 AM in response to Motagaly

Yes, every time TM runs without the external disk mounted you potentially have a problem.


If TM runs when the disk is dismounted, then next time the disk is mounted and TM runs - TM uses the 'Used' space on the drive in its calculations.


So,

A. if you keep the external drive mounted - you never have this problem, or

B. You have a problem if you dismount the disk, remount it and the free space on the TM drive is less than:

  1. the used space on the external disk, plus
  2. any deltas on other drives. plus
  3. the padding TM adds


Prior to Yosemite, in case B1, TM would scan the external disk and calculate the true difference between what was on the external disk and the previous backup for that disk so this problem didn't arise.


Your choices are:

1. Turn TM off before you dismount the disk and turn it back on after you have remounted it, not good because it means other disks are not being backed up, or

2. Keep the external disk mounted all the time, not good because it should not be necessary (and was't in Mavericks) or

3. Keep lots of free space on the TM disk

Aug 20, 2015 8:17 AM in response to ItWasNotMe

Thanks so much for the detailed explanation,


I will personally go with Choice 1 as I am using a MacBook Pro 15" mid 2014, and with mobility, I can't have the 2 external drives (work and Photography) attached all the time, I just placed an order for the new 12 TB WD my book Duo, as my total Backups went beyond 3 TB, so choice 3 will take effect once I get it in RAID1 6TB storage.


Sure I will mount them later (with choice 3) one by one (TM backups in between), other wise TM will want their combined space which will exceed my limits.


I believe your posts helped me so much understanding choices and how to overcome that bad implementation done by Apple in 10.10, hope El Capitan solve this soon.


Thanks again,

Yosemite and Time Machine

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