[Bug 120375] Re: cannot boot raid1 with only one disk

[Dustin Kirkland]

On Fri, Jul 25, 2008 at 8:08 PM, ceg <c.gatzemeier at tu-bs.de> wrote:
> "mdadm --run --scan" will start all arrays degraded not only the one needed for the rootfs (and
> its lvm and crypt respectively).
> It will start for example a partial array from a removable disk that was attatched and hasn't been
> forgotten when the computer was turned off. Remember starting an array degraded means it will
> also start degraded next time. To prevent accidential degration and sideeffect just start the
> required arrays with "mdadm --run /dev/mdX" or even better by UUID.
...
> Another point are required non-root filesystems, like a /home array that
> needs to startdegraded.
...
> We need a way to configure non-root raid devices to startdegraded
> anyway, so this configuration could as well be used (hooked into
> initramfs like the cryptroot script does) for the root device. (The
> bootdegraded kernel parameter might not be neccesary then.)

I agree that my patch might start more degraded raids than someone may
necessarily want, but the current bug and the current issue at handle
is about providing a mechanism to configurably allow booting if a RAID
is missing a disk.  This bug already has 73+ comments, and has been
around for over a year.  Let's fix at least the immediate problem at
hand.

What you're talking about is going to be more complicated, and can be
handled at a later time, by subsequent patches.  How about opening a
separate bug for independently allowing/disallowing each array to be
started in degraded mode?

> This means of course we need to know the required array in initramfs.

Well, that part is doable for the root filesystem at least.  It's
${ROOT} within the initramfs scripts.

:-Dustin

:-Dustin

-- 
cannot boot raid1 with only one disk
https://bugs.launchpad.net/bugs/120375
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