ChrisJenkins

Q: Network time machine backups fail to create initial backup

I have a Mac Mini running OS X 10.11.5 and OS X Server 5.1.5. One of the many services that I use on this server is the network Time Machine server. I have three client machine that have been happily backing up to this server for several years now. A couple of weeks ago some kind of problems was encountered by two of the clients and their backups failed (I was not able to diagnose the issue then as it was the day before we were due to go on vacation, so I just removed the network destination from the backup list on both machines [they also backup to a local disk drive]).

 

Having cleared down the old (maybe damaged) backups on the server and verified (from the command line that they had gone), I tried starting a new backup to the network location from one of the clients. This fails after (quite) a while with the following error:

 

Screen Shot 2016-07-23 at 11.08.03.png

 

The sparsebubndle disk image has been created (though it is very small) and the underlying network volume (/Volumes/TMNetwork1) is mounted on the client and accessible, as is the disk image. In the system log all I see are repeated attempts to unmount /Volumes/TMNetwork1 which are being denied by disk arbitration due to mds accessing the volume. I have tried cleaning everything up and rebooting the client, and even the server, and still it keeps failing in the same way.

 

Any suggestions on how to troubleshoot this? The problem seems like a client side issue but I wonder...

Posted on Jul 24, 2016 8:15 AM

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Q: Network time machine backups fail to create initial backup

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  • by Linc Davis,

    Linc Davis Linc Davis Jul 25, 2016 10:43 AM in response to ChrisJenkins
    Level 10 (207,926 points)
    Applications
    Jul 25, 2016 10:43 AM in response to ChrisJenkins

    Please open the Time Machine preference pane on the client and delete the backup destination. Then add it back. Any change?

  • by ChrisJenkins,

    ChrisJenkins ChrisJenkins Jul 26, 2016 12:19 AM in response to Linc Davis
    Level 1 (15 points)
    Apple Music
    Jul 26, 2016 12:19 AM in response to Linc Davis

    I'd already tried that (several times) to no avail. However, I have resolved the problem... It turns out that the disk on the server holding the Time Machine disk images was going bad. There hadn't been any noticeable issues on the server side until yesterday when an overnight image backup to a different partition on that disk failed due to a large number of disk errors. I replaced the disk yesterday and re-setup the necessary network Time Machine config and now the network TM backup from the clients has completed just fine.

     

    So, a bad disk was the culprit.