RAID problems, cant choose my system HD

Question

hi there
i recently added an old 40GB HD to my AGP Powermc G4, whose system HD is 80 GB (15GB left)
i wanted to join the two together in a striped RAID set-up so that things like iMovie run faster, but when i use disk utility and it prompts me to drag two volumes into the RAID space, i can select the 40 GB but not the system HD
any ideas why not??? the help utility says that RAID setups cant be perfromed on disks that are partitioned, mine apparently has an apple map partition (no idea what it is or how it got there!)...is this the problem?
thanks a bunch

Answer 1

Hi-
I think you may be going about this a bit wrong. I am going to give you a couple links to read:
Please read about RAID 0
http://docs.info.apple.com/article.html?artnum=106594
Steps to set up a mirror RAID (1), though basically apply to RAID 0:
http://www.frozennorth.org/C2011481421/E20060221212020/
In the readings, you will notice that:
-The setup of the RAID is part of the installation process (requiring initializing/erasing of the hard drives).
-Using different size drives will result in a RAID 0 equal to the size of the smaller drive.
-Backing up all system software is important prior to starting the setup.
Your hard drive has an Apple partition map as part of the initialization (formatting) process. To have "partitions", at initial install of the software on a drive, one must use Disk Utility to create the partitions, which will be seen as seperate volumes (like seperate drives, only on one drive).
If you have the partitions in place, origionally, you could proceed as you are trying. To do so now, will require the erasing, reformatting, and partitioning of the drive. You will then need to reinstall all software and files.
In the frozen north link, the explanation of using an external drive, to back all files to, prior to setting up the drives for RAID, is as I would advise you to do.