RAID 5+1 with mdadm

RAID 5+1 with mdadm

[Peter Krauss]

Hello,

I am looking for a "step by step" webpage (or replied attach) for setup 
RAID 5+1

* RAID 5+1  (mirroring of RAID 5 sets)
* Linux Debian Lenny
* using mdadm (!?)
* 6 discs ~1.3 Tb

A recipe like

http://svn.debian.org/wsvn/pkg-mdadm/mdadm/trunk/debian/README.recipes?op=file&rev=0&sc=0 



is sufficient (!).

... or a a secure information about raid 5+1 installation steps: first 
RAID 0+1, then RAID 5?

thanks,
   Peter Krauss

Re: RAID 5+1 with mdadm

[Stan Hoeppner]

Peter Krauss put forth on 9/15/2010 4:24 PM:
> Hello,
> 
> I am looking for a "step by step" webpage (or replied attach) for setup
> RAID 5+1

You probably won't find one, unless someone writes one just for you.
RAID 5+1 is very non-standard.  In fact I've never heard of anyone using
it, only as a theoretical possibility.  RAID 50, or 5+0, is far more
common, and it itself is not very common overall.

Your goal will require nesting of RAID groups--nesting of md devices.
You're going to need to create two RAID5 md devices and then make a
RAID1 device from the two RAID5 devices.  If you already know how to
create a RAID5 md device and a RAID1 md device, this should be a piece
of cake.

Keep the mdadm man page open while you do it just in case.  The only
thing you really need to be concerned with are the chunk and stripe
sizes, which can get complicated when creating nested arrays.  I have no
idea what those parms should be for a 6 disk nested RAID5/1.  Maybe
someone here can help.

Good luck.

-- 
Stan