conversion from lower to higher RAID levels in RAIDframe

[George Michaelson <ggm%pobox.com@localhost>]

Forgive a naieve question, a question which probably goes to the heart  
of "if you don't understand RAID you shouldn't be using it" land.

Am I right in thinking that you do *NOT* get free uplifting from  
RAIDframe to convert RAID0 to RAID1, and RAID1 to RAID5? There isn't  
some low level tech which does this for you?

That, you have to take data *off* the old stripe-state to somewhere  
else, and then re-write it back into the clean, parity-initialized new  
RAID<n> level that you are 'upscaling' into?

It looks that way. I can see some path(s) to removing RAID1 mirror  
pairs, and then having single-spindles to use, to hold data, pending  
re-creation of the higher RAID level. But, there isn't a clean path-in- 
one, its do it by hand.

Yes/No?

(RAID1 is distinct from RAID0 in this respect, because RAID1 iirc  
correctly either 'side' of the mirror pair is inherently a valid  
filesystem, so you can  run RAID1 with only one disk from a 2-mirror  
pair. RAID0, you are striping and so removal of any disk invalidates  
the 'upper' filesystem layer inherently. Since I have RAID1+0, I can  
remove one RAID1 disk from each RAID1 sub-instance, which then can be  
used to make the upper level RAID5 state from three RAID1 mirrors,  
but, I am not convinced I can keep the valid FS state in that RAID5 in  
the act of initializing it.)

-George