From: Miquel van Smoorenburg <mikevs@xs4all.net>
To: Chris Murphy <lists@colorremedies.com>
Cc: Linux RAID <linux-raid@vger.kernel.org>
Subject: Re: GPT Table broken on a Raid1
Date: Tue, 25 Sep 2012 09:33:45 +0200 [thread overview]
Message-ID: <50615E59.9070503@xs4all.net> (raw)
In-Reply-To: <8AB64122-6198-4A2E-BA49-76BD6AFE7907@colorremedies.com>
On 24-09-12 7:35 PM, Chris Murphy wrote:
> Further, it seems increasingly clear as I'm reading the UEFI spec on
> GPT, that IMSM is incompatible with GPT. The GPT alternate header by
> spec is expected at the end of the disk, but then IMSM also demands
> to be in basically the exact same location. And yet Intel is shipping
> UEFI hardware, which require GPT disks, with IMSM on board that also
> requires metadata in the same location? How is this not a WTF
> moment?
It isn't. It's just RAID setup with the superblock at the end of the
disk- as soon as RAID1 is activated, the RAID volume you see is just a
bit smaller than the raw disksize, and the GPT alternate header is at
the right place- at the end of the RAID volume.
The thing is that the Linux kernel detects the GPT partition table on
the raw disks before the RAID1 volume is assembled. More of a cosmetical
bug.
People have argued before that the kernel should do no partitiontable
discovery at all, and just leave it to userspace. That's what kpartx is
for, for example. In that case, with a correctly ordered and configured
stack, the disks would get detected, any whole-disk RAID volumes would
get assembled, and only then partition detection would be done. But I
think that never got popular because of all the "I want to boot a kernel
without an initramfs" people.
Mike.
next prev parent reply other threads:[~2012-09-25 7:33 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-19 11:03 GPT Table broken on a Raid1 Günther J. Niederwimmer
2012-09-20 2:39 ` Chris Murphy
2012-09-20 11:05 ` Günther J. Niederwimmer
2012-09-20 17:34 ` Chris Murphy
2012-09-21 11:42 ` Günther J. Niederwimmer
2012-09-21 19:35 ` Chris Murphy
2012-09-21 22:43 ` Chris Murphy
2012-09-22 8:37 ` Günther J. Niederwimmer
2012-09-22 18:30 ` Chris Murphy
2012-09-23 6:47 ` Hello,Re: " Günther J. Niederwimmer
2012-09-23 7:17 ` Chris Murphy
2012-09-24 7:28 ` Günther J. Niederwimmer
2012-09-24 17:21 ` Chris Murphy
2012-09-24 19:06 ` Günther J. Niederwimmer
2012-09-24 20:18 ` Chris Murphy
2012-09-24 21:06 ` Günther J. Niederwimmer
2012-09-24 21:12 ` Chris Murphy
2012-09-25 8:27 ` Günther J. Niederwimmer
2012-09-25 9:28 ` John Robinson
2012-09-25 16:55 ` Chris Murphy
2012-09-26 12:17 ` Günther J. Niederwimmer
2012-09-26 19:33 ` Chris Murphy
2012-09-27 2:43 ` NeilBrown
2012-09-22 15:31 ` John Robinson
2012-09-22 18:45 ` Chris Murphy
2012-09-22 21:58 ` NeilBrown
2012-09-22 22:07 ` John Robinson
2012-09-22 22:30 ` Chris Murphy
2012-09-23 12:00 ` John Robinson
2012-09-23 17:44 ` Chris Murphy
2012-09-23 18:53 ` Chris Murphy
2012-09-24 9:37 ` John Robinson
2012-09-24 17:35 ` Chris Murphy
2012-09-24 18:17 ` Roberto Spadim
[not found] ` <CABYL=ToFtzXv95At54=jSCaD0QVSB+bdxbssda1AMw5gNBqvhg@mail.gmail.com>
2012-09-24 18:55 ` Chris Murphy
2012-09-25 7:33 ` Miquel van Smoorenburg [this message]
2012-09-21 21:30 ` Chris Murphy
2012-09-21 21:49 ` Chris Murphy
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