i will note that ODS allows mirrored root filesystems.  i don't remember
anything about disallowing stripping or concatenating them, either, but
they will ignore the disklabel/bootblock portion on  disk.

i like parts of ODS:  it keeps state in dedicated partitions on the
disk, a metadevice db "replica".  you create several of these partitions
on your disks and it uses them to keep state -- each one is independant
or the others.

i also like the model of ODS (as under solaris 2):
	- a metadevice acts like a normal disk partition
	- a metadevice can be composed of any number of real partitions
	  or metadevices, either concatenated or striped, or mirrored.

you create a mirrored stripe by creating two (or three -- ODS has an,
IMO, stpuid limit) stripes and then mirroring these two metadevices.


recent ODS versions include raid5 support, file system extensions, etc.


i'm fairly conversant in ODS if anyone has other questions.