daisy chaining

[sdsl]

Originally Posted by mirgilwin

I have an OWC 800FW drive that I use for Time Machine, I have a LaCie 800FW that I use for SD. I run SD at 1 in the morning, TM at 12 hour intervals that don't coincide with the time SD is backing up.

I have been using USB400 to backup the LaCie, my question is:
can I daisy chain the LaCie to the OWC and use firewire for both?

Additionally, if they both happen to be backing up at the same time, will that cause the heavens to fall?

I have daisy chained firewire drives on Imacs running 10.4.11 and 10.3.9 and on an Intel Mac running 10.4.11. I have used Super Duper with no problems with one or the other of the daisy chained drives.

I think you could also use Time Machine and Super Duper at the same time except for the following:

- much slower performance due to sharing the same firewire cable into your Mac and having to take turns with I/O. There is overhead associated with this.

- once in a while you could cause one or both programs to really hang if they try to access the same file at the same time. This seems unlikely but if you have one or more very large files, it is probably going to happen at some point in the future. It seems to me that it would be best to time things so the two program have no chance of running at the same time. You should eliminate any chance of complications with things as important as backups.

- from a risk perspective, you are asking for trouble running two backup programs at the same time. Imagine that the two programs interfere with each other and hang your computer in such a way that you have to power down with the power button. This could damage your system or file catalog such that your computer refuses to boot, and it could damage some of your files as well. But then you'd have a damaged hard disk plus two unusable backups, hence you could totally lose your data with no recourse. You should in fact have a policy of not having the redundant backups powered up at the same time even. Another example of why: a power failure could hose your main computer disk plus both backups if all three are active at once.