Re: Raid 10 question/problem [ot]

[Michael Tokarev <mjt@tls.msk.ru>]

Jan Engelhardt wrote:
> On Jan 27 2007 10:31, Marc Perkel wrote:
[]
>> Sorry about that. I'm using Fedora Core 6. /dev/md0
>> and /dev/md1, buth of which are raid 1 arrays survive
>> the reboot. But when I make a raid 0 out of those two
>> raid arrays that's what is vanishing.
> 
> That's interesting. I am using Aurora Corona, and all but md0 vanishes.
> (Reason for that is that udev does not create the nodes md1-md31 on
> boot, so mdadm cannot assemble the arrays.)

This is nonsense.

Mdadm creates those nodes automa[tg]ically - man mdadm, search for --auto.
Udev has exactly nothing to do with mdX nodes.

In order for an md array to be started up on boot, it has to be specified
in /etc/mdadm.conf.  With proper DEVICE line in there.  That's all.

If you're using raid0 on top of two raid1s (as opposed to using raid10
directly - which is more efficient and flexible), the DEVICE line in
mdadm.conf should be either `partitions' (usually preferred way), or -
in case direct device list is specified - should contain both real
disks AND the raid1 arrays.

But in any case, this has exactly nothing to do with kernel.
It's 100% userspace issues, I'd say distribution-specific issues.

/mjt