From: John Robinson <john.robinson@anonymous.org.uk>
To: Chris Murphy <lists@colorremedies.com>
Cc: Linux RAID <linux-raid@vger.kernel.org>
Subject: Re: GPT Table broken on a Raid1
Date: Sun, 23 Sep 2012 13:00:51 +0100 [thread overview]
Message-ID: <505EF9F3.7000908@anonymous.org.uk> (raw)
In-Reply-To: <6FBE5434-A133-43C0-8296-58978301D32B@colorremedies.com>
On 22/09/2012 23:30, Chris Murphy wrote:
> On Sep 22, 2012, at 4:07 PM, John Robinson wrote:
[...]
>> I'm saying that when the Linux kernel boots, and the AHCI driver starts, it sees the IMSM member discs as raw discs, which get probed for partitions. The GPT partition probe spots one of the copies of the GPT partition, but can't find the other one because the IMSM metadata's there.
>
> The IMSM metadata will go at the end of the PHYSICAL disk. If you partition the virtual disk, i.e. the array, /dev/md/imsm0, then the GPT alternate header goes at the end of the virtual disk, NOT the end of the physical disk.
That's right. But the main GPT partition table will go at LBA=1 of the
virtual disc, which maps to LBA=1 of the physical disc. So when the
physical disc gets probed for partitions, the main GPT partition table
is visible at LBA=1, but there isn't a secondary GPT partition table at
the end of the disc, hence the error.
Cheers,
John.
next prev parent reply other threads:[~2012-09-23 12:00 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 [this message]
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
2012-09-21 21:30 ` Chris Murphy
2012-09-21 21:49 ` Chris Murphy
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