Kernel Panics when partitioning FW800 drive

Hi everyone,

I am having a peculiar problem. I have a 1TB LaCie external drive connected to my MacBook Pro via FW800. I would like to split the drive into 2 even partitions. There is already some data on the drive, but not much (there will be plenty of room to spare on the already-used new 500GB partition).

It's my understanding that OS X will "reorganize" (defrag?) the data on the drive to configure the new partition, without deleting the data. Am I correct?

Well, I have tried multiple times to do a simple split partitioning this drive, and after a minute or so, my Mac completely crashes. I force a reboot, Repair Disk since it crashed in the middle of partitioning and the disk shows errors, and try again: crash.

I am in the process of simply moving all the data off the drive onto another one. Erasing the LaCie drive completely and partitioning (hopefully) from there.

But, I shouldn't have to do this. What's going on? Is OS X having trouble moving the data around to set up the partitioning? Is there some bug with FireWire drives?

FWIW, the drive is in Mac OS Extended Journaled format with GUID partition table.

Thanks everyone,
William

Update: after erasing the drive completely, partitioning worked. So, hooray. But why did this problem happen in the first place? I'd just kinda like to know for future reference.