RAID 1 on top of RAID 0

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pk

What would the outcome be of a RAID controller creating a RAID 0 array
and then someone creating a software RAID 1 on top of it? It sounds
extremely messed up and unfortunately I believe I've just inherited
this. Is there any way to just create a hardware RAID 1 out of this,
or is it not as bad as I think it is?

Thanks.

pk
 
pk said:
What would the outcome be of a RAID controller creating a RAID 0 array
and then someone creating a software RAID 1 on top of it? It sounds
extremely messed up and unfortunately I believe I've just inherited
this. Is there any way to just create a hardware RAID 1 out of this,
or is it not as bad as I think it is?

Thanks.

pk
Click to expand...

That is a pretty standard arrangement. In simplest form, use 4 HDs, then
create a pair of RAID0 arrays, then create a RAID1 array whose members
are the two RAID0 arrays. This gives you high performance (from striping
with RAID0) and reliability (from mirroring with RAID1).
 
Hmm, I should have been clearer. There are only 2 hard drives in this
setup. I don't have any sort of redundancy or speed increase, do I?
I'm having trouble visualizing it.
 
pk said:
Hmm, I should have been clearer. There are only 2 hard drives in this
setup. I don't have any sort of redundancy or speed increase, do I?
I'm having trouble visualizing it.
Click to expand...

Not enough info to tell, but you sure aren't getting all the benefits I listed
in my note on normal RAID1 on RAID0, since that requires at least 4 HDs.

If both HDs are members of a RAID0 array, then RAID1 on top of that is a waste
and probably causes a tiny bit of lost performance. If each HD is the only
member of a RAID0 array, then the RAID0 is a waste (i.e., no performance gain),
but RAID1 still gets you data integrity via redundancy.
 
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