Re: striping and mirroring with only two disks

On Mon, Feb 02, 2004 at 03:58:27PM +1100, Neil Brown wrote:

On Sunday February 1, keld@dkuug.dk wrote:

I started work on a "raid10" personality a while back, which could do
what you describe, or could stripe/mirror across 3 drives and other
combination.

Sounds like the RAID1E and RAID5E of some of the IBM ServeRAID controllers...

1E: Works across minimum of 3 drives, with the stripes written as:

Drive: 1 2 3
       a b c
       b c a
       d e f
       e f d

Ie. you still lose half the disk space, but will work over unequal
 number of wrives with still a single drive failure resilience and a full
 speed read.


5E: minimum 4drives, similar story just a tad different (No, I've mislaid
the documentation :()