Re: [gentoo-user] Software RAID-1

[Kerin Millar <kerframil@fastmail.co.uk>]

On 25/08/2014 12:17, Peter Humphrey wrote:

<snip>

> Well, it was simple. I just said "rc-update del mdraid boot" and all is now
> well. I'd better revisit the docs to see if they still give the same advice.
>
> -- Regards Peter

Very interesting indeed. I now wonder if this is a race condition 
between the init script running `mdadm -As` and the fact that the mdadm 
package installs udev rules that allow for automatic incremental 
assembly? Refer to /lib/udev/rules.d/64-md-raid.rules and you'll see 
that it calls `mdadm --incremental` for newly added devices.

With that in mind, here's something else for you to try. Doing this will 
render these udev rules null and void:

# touch /etc/udev/rules.d/64-md-raid.rules

Thereafter, the mdraid script will be the only agent trying to assemble 
the 1.x metadata arrays so make sure that it is re-enabled.

I'm not actually sure that there is any point in calling mdadm -As where 
the udev rules are present. I would expect it to be one approach or the 
other, but not both at the same time.

Incidentally, the udev rules were a source of controversy in the 
following bug. Not everyone appreciates that they are installed by default.

https://bugs.gentoo.org/show_bug.cgi?id=401707

--Kerin