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Re: RAID10 on Debian (or RAID0 on top of RAID1) - possible?

On Wed, 9 Aug 2006, Gilles Mocellin wrote:

Le mercredi 9 août 2006 16:18, Tomasz Chmielewski a écrit :
I wanted to install a Debian system on RAID-10, on 4 disks.
Unfortunately, it seems that Debian installer only supports RAID0, RAID1
and RAID5.

As RAID-10 is technically RAID-0 on top of RAID-1s, I tried such a


    R1          R1


Unfortunately, Debian installer is also unable to create such a setup -
it seems that it can't create RAID devices on existing RAID devices
(i.e., RAID-0 on RAID-1).

How can I set up RAID-10 (or RAID-0 on top of RAID-1) using the Debian

I don't think it's possible with the installer, but you can do stripped LVM
(lvcreate's -i option) above RAID-1, it's quite RAID-10.

I would not recommend LVM unless you don't care about throughput, see below:

Date: Mon, 07 Aug 2006 13:04:55 -0700
From: Shane <shane@cm.nu>
To: linux-raid@vger.kernel.org
Subject: Re: raid5/lvm setup questions

On Mon, Aug 07, 2006 at 08:57:13PM +0100, Nix wrote:
On 5 Aug 2006, David Greaves prattled cheerily:
> As an example of the cons: I've just set up lvm2 over my raid5 and
> testing snapshots, the first thing that happened was a kernel BUG and

I've been backing up using writable snapshots on LVM2 over RAID-5 for
some time. No BUGs.

Just performed some basic throughput tests using 4 SATA
disks in a raid5 array.  The read performance on the
/dev/mdx device runs around 180mbps but if lvm is layered
over that, reads on the lv are around 130mbps.  Not an
unsubstantial reduction.

I seem to recall patches to md floating around a couple
years back for partitioning of md devices.  Are those still
available somewhere?


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