From mboxrd@z Thu Jan  1 00:00:00 1970
From: John Drescher <drescherjm@gmail.com>
Subject: Re: raid5 Unplug the disk
Date: Wed, 28 Jan 2015 11:59:30 -0500
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To: lilofile <lilofile@aliyun.com>
Cc: stan <stan@hardwarefreak.com>, Linux RAID <linux-raid@vger.kernel.org>
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On Wed, Jan 28, 2015 at 1:44 AM, lilofile <lilofile@aliyun.com> wrote:
> kernel  linux 3.10, centos
> when I use 5 disk to create raid5,after sync complete, I unplug a disk,and wait a moment, then replug the same disk.
>
> the original 4 disk are still a raid5 which is degraded.
> I find the single disk  become a new raid5,but inactive,what the reason?

stop whatever new array that shows up then use

mdadm --manage /dev/mymddevice --re-add /dev/disk5

John