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Old 09-14-2008, 11:17 AM
acronce acronce is offline
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Join Date: Aug 2006
Posts: 10
SD not unmounting sparse image volumes

Hi all,

I've got two scenarios where sparse image destinations are not being unmounted after their respective backups. Ideally I want this to work with scheduled backups. But manual backups fail to unmount in exactly the same way.

I've reviewed the user's manual, searched this forum, and done numerous experiments. But I just can't get this to work. I know that I can use scripts to unmount the volumes. But it seems that since SD is supposed to do this for me under certain scenarios, I'd prefer to work within SD's parameters rather than try to just fall back to scripts.

Scenario 1 - backup to local sparse image bundle:
In this case, I'm backing up a boot drive to a sparse image bundle on an external RAID array. The reason why I'm using a bundle as the target, is because the RAID array itself is backed up later over the network. Using a bundle minimizes the work needed for this backup because only the changed bands need to be copied.

When the volume associated with the sparse image bundle is not mounted, SD mounts it, does the backup, then doesn't unmount it. This is a problem for me because I want to periodically compact the sparse image bundle, driven by a post backup script.

Scenario 2 - backup to encrypted sparse image on an AFP share:
In this case, I'm backing up the external RAID array mentioned above to an encrypted sparse image file on an AFP volume. Again, if the AFP volume and the contained sparse image backed volume are not mounted, SD mounts them. But after the backup, neither are unmounted. This is a problem because we want to do periodic maintenance on the AFP server.

According to the documentation, a network mounted sparse image file will be unmounted after the backup. The subtlety, according to posts to this forum, is that this only works when the target backup known to SD is an image file.

However in both of my scenarios, the backup target is a sparse image that I had to create in Disk Utility. SD doesn't directly support the ability to create either an encrypted or bundle image. But it also doesn't let me target an existing bundle or image file. The UI will only let me create a target sparse image file. As a result, I've had to mount my bundle and encrypted image, then target the volume in SD.

I seem to be in a catch 22, where SD has its own internal rules for when to unmount the target image, but I can't configure it to do for my particular scenarios. It would be nice if a future version of SD just allowed me to specify to unmount the target, regardless of its internal logic.

Thanks in advance for any suggestions.

Best regards,
Allen Cronce

Last edited by acronce; 09-14-2008 at 11:21 AM.
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