This behavior is documented in the "About your Power Macintosh G3" Read Me preinstalled on the hard drive of the Power Macintosh G3 (Blue and White) computers. With the release of the iMac and later computers, Apple moved to a new Mac OS ROM architecture. This new architecture does not recognize multiple striped devices as a valid startup disk.
Workaround
Create 2 different volumes where one is either standard or mirrored (the startup volume) and the other is striped (the storage volume).
One would do this as follows:
- From within SoftRAID create a small Standard or Mirrored volume (big enough to store a System Folder as your startup volume).
Note: This volume CANNOT be a Striped volume. For example, create a mirrored 200 MB volume using both drives.
- Next, allocate the remainder of the space as a striped storage volume. Install the system software onto the smaller, non-striped volume and set the Startup Disk control panel to boot from this volume.
- After restarting, the computer should now boot from the smaller mirrored volume.