TM Local Backups keeps waking HD

Discussion in 'OS X Mavericks (10.9)' started by mcaswell, Dec 22, 2013.

  1. mcaswell macrumors regular

    Dec 22, 2013
    My Mac Pro has 2 SSDs and one hard drive. Since installing Mavericks a few days ago, I've noticed that the drive spins up about every 4 hours (with 10.8, this did not happen).

    I found a suggestion elsewhere to run fs_usage in Terminal to try and determine what process was the culprit, and I found these entries that coincide with the spin-ups:

    06:50:30 getattrlist /Volumes/RAW Files/.MobileBackups 0.000004 UserEventAge
    06:50:30 getattrlist /Volumes/RAW Files/.MobileBackups.trash 0.000003 UserEventAge
    06:50:30 lstat64 /Volumes/RAW Files/.MobileBackups 0.000003 UserEventAge
    06:50:30 getattrlist /Volumes/RAW Files/.MobileBackups.trash 0.000003 UserEventAge
    06:50:30 lstat64 /Volumes/RAW Files/.MobileBackups.trash 0.000003 UserEventAge

    Apparently MobileBackups has something to do with a feature of Time Machine called Local Backups or Local Snapshots. However, I don't use Time Machine, and it's switched off in the PrefPane. Furthermore, I ran the Terminal command to disable Local Backups.

    Any idea how to stop this from happening? Is some part of Time Machine still active and accessing volumes every 4 hours even though Time Machine is turned off? And if so, is there a way to completely disable it?

  2. mcaswell thread starter macrumors regular

    Dec 22, 2013
    Think I finally figured this out. For the sake of anyone else who encounters this issue at some point later, here's what found.

    After examining the fs_usage output and various log files (no easy task, since I know very little about all that stuff), I eventually determined that these MobileBackup events were caused by an installer... in this particular case, Sophos Anti-Virus.

    When the installer runs (completely in the background... I had no visual indication that this was occurring, only discovering it in the installer.log file), it apparently suspends backupd, then reenables it (despite Time Machine being turned off in the prefpane), and when this happens, the MobileBackups activity occurs (waking the drive).

    I checked the Sophos preferences, and sure enough, it's set to auto-update every 4 hours.

    Not sure why this didn't occur under Mountain Lion.


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