Thanks Myron - This is very useful information. This, combined with your link to the other post about excluding items from the safepoint backup explains some of the behavior that I was seeing while experimenting with the Safepoint backup and restore.
I wanted to point out in my example 105 gig safepoint - about 45 gig of that was a Mac Time Machine sparse bundle image in the TimeMachine share (which probably consisted of 500,000+ files inside the Sparse Bundle) - and a 38 gig Norton Ghost v14 PC full image backup - and the rest about 22 gig of random files - probably a combo of music and photos.
The safepoint backup was taking forever gyrating through the Time Machine Sparse Bundle - and probably accounted for 85% of the backup time. At certain points it appeared to be just stuck - but the drive was clicking away. I did a subsequent test of the safepoint creation after deleting the Sparse Bundle image from the drive - and the creation was exponentially faster. The Norton Ghost image file did not seem to impact the performance of the Safepoint Creation but the Sparse Bundle seems to have brought the creation process to a crawl.
I would think that a typical WD MyBook Live user would have a variety of different types of data stored on the drive - probably various backups from other systems, files that are stored on the NAS simply for convenience (not necessarilyt needing to be backed up) - and critical data that is stored only on the NAS and needs to be backed up. It would be really nice (as you stated in your other post) to be able to specify safepoint exclusion criteria for the safepoint backup - ultimaly limiting the spaced needed and time required to create/update the safepoint - making it possibly to use a variety of other shared drive resources on the network rather than having to have a stand-alone MyBook Live drive sitting around to hold safepoints.
In my case I don’t necessarily want to back up my backup files on my safepoint - and would like to exclude them. I will take a closer look at your other post on how to exclude specific items.
I am somewhat proficient with linux and perl - however I have no experience with rsync. Do you happen to have a link that provides a good explanation of how to use the rsync utility? I’m sure I can Google that - however - I suspect you might be able to point me to something that will be better than what I might find on my own.