On Mon, Feb 06, 2006 at 06:47:54PM -0800, H. Peter Anvin wrote:
Neil Brown wrote:
Requiring that mdadm.conf describes the actual state of all volumes
would be an enormous step in the wrong direction. Right now, the Linux
md system can handle some very oddball hardware changes (such as on
hera.kernel.org, when the disks not just completely changed names due to
a controller change, but changed from hd* to sd*!)
ARRAY /dev/md0 UUID=xxyy:zzyy:aabb:ccdd
would catch that
Dynamicity is a good thing, although it needs to be harnessed.
> kernel parameter md_root_uuid=xxyy:zzyy:aabb:ccdd...
> This could be interpreted by an initramfs script to run mdadm
> to find and assemble the array with that uuid. The uuid of
> each array is reasonably unique.
I could change mdassemble to allow accepting an uuid on the command line
and assemble a /dev/md0 with the specified uuid (at the moment it only
accepts a configuration file, which i tought was enough for
This, in fact is *EXACTLY* what we're talking about; it does require
autoassemble. Why do we care about the partition types at all? The
reason is that since the md superblock is at the end, it doesn't get
automatically wiped if the partition is used as a raw filesystem, and so
it's important that there is a qualifier for it.
I don't like using partition type as a qualifier, there is people who do
not wish to partition their drives, there are systems not supporting
msdos like partitions, heck even m$ is migrating away from those.
In any case if that has to be done it should be done into mdadm, not
in a different scrip that is going to call mdadm (behaviour should be
consistent between mdadm invoked by initramfs and mdadm invoked on a
If the user wants to reutilize a device that was previously a member of
an md array he/she should use mdadm --zero-superblock to remove the
I see no point in having a system that tries to compensate for users not
following correct procedures. sorry.
Luca Berra -- [email protected]
Communication Media & Services S.r.l.
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