From: NeilBrown <neilb@suse.de>
To: Oleg Samarin <osamarin68@gmail.com>
Cc: linux-raid@vger.kernel.org
Subject: Re: How does linux hide underlying disks partitions?
Date: Sat, 30 May 2015 07:14:26 +1000 [thread overview]
Message-ID: <20150530071426.75a7302e@notabene.brown> (raw)
In-Reply-To: <1432926434.4733.1.camel@gmail.com>
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On Fri, 29 May 2015 22:07:14 +0300 Oleg Samarin <osamarin68@gmail.com> wrote:
> I'm trying to evaluate a complex mdadm-lvm-udev-anaconda issue
> https://bugzilla.redhat.com/show_bug.cgi?id=1226305 and to undestand
> how mdadm works.
>
> I have an intel imsm raid-1 volume /dev/md126 assembled with two
> disks /dev/sda and /dev/sdb.
> This volume has two partitions /dev/md126p1 and /dev/md126p2.
>
> Because it a simple mirror, both disks have te same information.
>
> When the normal system boots up, I can see with journalctl that
>
> 1. at first /dev/sda1, /dev/sda2, /dev/sdb1, /dev/sdb2 appear
> 2. then mdadm assembles /dev/md126 from /dev/sda and /dev/sdb
> 3. /dev/sda1, /dev/sda2, /dev/sdb1, /dev/sdb2 disappear
> 4. /dev/md126p1 and /dev/md126p2 coming instead
>
> Which program component is responsible for
> disappearing /dev/sda1, /dev/sda2, /dev/sdb1 and /dev/sdb2?
mdadm has a function "remove_partitions" which uses the BLKPG ioctl to tell
the kernel to forget about the partitions.
>
> Why can they be left after starting anaconda installer?
I don't know anything about anaconda - maybe someone else can help.
NeilBrown
>
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prev parent reply other threads:[~2015-05-29 21:14 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-29 19:07 How does linux hide underlying disks partitions? Oleg Samarin
2015-05-29 21:14 ` NeilBrown [this message]
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