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Disk Ownership / Permissions

LBackup instructs RSync to preserve permissions by default.

Permission on OS X Volumes

To preserve permissions on local volumes under OS X it is important to ensure that the “Ignore Permissions” / “Ignore ownership on this volume” options is unselected on your backup drive. If this options is selected then the permissions are ignored and it will not be possible for Backup to preserve the permissions of directories and files copied to the backup volume(s). Therefore, it is recommended that this option is left un-checked on source and destination volumes. Although backups may work with this option checked, it is not tested or recommended.

To set this option on and off first select the drive. Next select 'Get Info…' under the 'File' drop down menu. Finally, either check or un-check the appropriate check box. You may need to first click the disclosure triangle for the drive permissions.

Check Ignore Permission Status Using the Terminal

It is also possible to check and even enable these permissions from the command line :

Check Permissions On Volume

vsdbutil -c /Volumes/VolumeName

Activate Permissions on Volume

sudo vsdbutil -a /Volumes/VolumeName

Ignore Permissions on Volume

sudo vsdbutil -d /Volumes/VolumeName

    NOTE : vsdbutil has been depreciated (using diskutil) is now recommended.

Advanced Permission Options and Approaches

OS X offers a number of ways to enable and disable volume permissions. As such, some advanced options are listed below which relate to different ways of dealing with permissions on the backup destination.

Bypass LBackup Checks For Permissions On The Destination Volume

Specifying the following line within your LBackup configuration on a Darwin system will disable the checks for permissions on the destination volume.


An example of when this may be useful is if you mount a disk image using the following example command :

hdiutil attach -owners on /Volumes/Backup_Volume/backupimage.sparsebundle

In the example above the -owners on is passed to hdiutil and as such, it my be useful to disable the halting of the backup just because the vsdbutil database has no recored for the permissions being enabled for the specified destination backup volume.

Other Mac OS X Volume Configuration Options

It is also recommended that you ensure access control lists are enabled on any backup volumes.

Related Links