Random Booting on MAC pro with 2 harddrives

[chris_johnsen]

Originally Posted by pavlov0032

I remember there was a choice to make it bootable or not..cant find it now..

First, SuperDuper! will always try to make it possible to boot a destination volume if the source volume was bootable. This does not mean that the machine will automatically boot from such a destination volume later, just that it will be possible to do so through either the System Preferences Startup Disk panel or booting with Option held down.

That said, the option Dave was talking about can be found from the main window: click the Options… button, in the General tab, for the On successful completion pop-up list, choosing either Restart from <target> or Set <target> as Startup Disk will cause SuperDuper! to change which volume is the default startup volume.


Currently, I have no internal drive in my system and just an external Firewire drive with 3 bootable partitions. I have found that although I have one of those volumes set to be the default startup volume, sometimes another volume is actually booted. I think it had something to do with the Firewire drive being spun down (though powered on) when I tried to boot my machine. Imagine this sequence of events:

Your system is powered up.
Both internal drives get power and start spinning-up and initializing.
The firmware goes through its early self-tests and initializations.
The drive in “bay 2” becomes ready.
The firmware is ready to boot the OS.
The firmware looks for its configured startup volume on the “bay 1” disk. It can not access that disk because it is not yet ready.
The firmware does find a bootable volume on the “bay 2” disk, however. Lacking any other alternative, it boots the volume from the “bay 2” disk. ★
The drive in “bay 1” becomes ready, but the firmware has already started booting from a volume on the “bay 2” disk.

(★ This step is hypothetical. I am not sure this is how Apple's EFI works, but I have seen something similar to this on my OpenFirmware machine.)

If the “bay 1” disk is only sporadically slow to finish “getting ready”, that might explain the ‘random’ starts from the second disk.