07-30-2011, 07:57 AM

I couldn't find a clear answer to this. Perhaps someone else has already researched it...

The internal drive on my MBP is currently partitioned so that I can dual boot either Snow Leopard or Lion. Now that I have Lion set up, I tried to start a new Time Machine backup. I assumed I'd have one backup for SL and another for Leopard. But TM wants to back up both partitions together.

This would be fine if the other partition was just being used as an external drive, but can SL and Lion share the same TM backup? This means depending on which OS is booted, that OS is going to want to write to the same backup. I'm suspect of allowing two OS to write to the same backup. Just sounds like a bad idea.

I guess I can exclude the partitions from backups in each of the OS. Or I could turn off TM in SL and just use the Lion TM to backup the entire drive.

07-30-2011, 11:09 AM

I would partition the backup drive to allow one for Lion and the other for SL and then setup Time Machine on both OSes to use the respective Time Machine partition.

Lion made some major changes to the way TM works and I'm fairly certain that letting both write to the same volume will lead to integrity issues with that backup drive.