Backup of live sparse images is ok?

[AusTxNerd]

First, I'm totally happy with Espionage. It's exactly what I've been looking for. Yea! No more FileVault mess.

My question is about the built-in backup feature of Espionage. I went through the forum post about correctly excluding things from Time Machine. That's fine. And I've setup the built-in Espionage backup to backup all of my encrypted folders to an external hard drive; upon unlocking and every hour while unlocked.

I'm surprised that it can backup the sparsebundle / sparseimage while that disk image is mounted. I thought that once a disk image was mounted you really couldn't (shouldn't?) mess with the underlying image file. I guess I'm mistaken since this seems to be how you're backing up the data. Any caveats? Or does it really produce a clean backup every hour while in use?

Thanks!
Mike

[greg]

Hey Mike, that's an excellent question. I'm actually not sure. Operating systems do support the notion of file locking, which prevents files from being written to while something is reading from them, but in UNIX (which is what OS X is basically), this is not always enforced. That is the only scenario where I could see a possibility of corruption happening, other than that it should be fine.

I would guess that the likelyhood of a corrupted backup is slim even when something is editing files inside of that sparseimage, but I cannot give you a definitive answer on that yet. I'll have to get back to you with a definitive answer, but in the meantime if you're concerned about this you can simply disabled that checkbox and simply have Espionage backup the folders only when the folders are locked (or via manually initiated backups).

[greg]

[AusTxNerd]

Greg,

Thank you so much for your research and your answer. No worries about the wait. Life is busy for me too!

Everything you've described makes sense. And I have tried mounting my backup images and everything seems fine for me as well.

So, thank you! It looks like the backup feature is doing exactly what it should be.

Mike

[greg]

No problem! Thanks for the question Mike!