From: NeilBrown <neilb@suse.de>
To: Ram Ramesh <rramesh2400@gmail.com>
Cc: Linux Raid <linux-raid@vger.kernel.org>
Subject: Re: mdadm --grow with --backup-file does not create backupfile?
Date: Mon, 13 Oct 2014 12:39:14 +1100 [thread overview]
Message-ID: <20141013123914.04b960ed@notabene.brown> (raw)
In-Reply-To: <543B2A2D.9080407@gmail.com>
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On Sun, 12 Oct 2014 20:26:05 -0500 Ram Ramesh <rramesh2400@gmail.com> wrote:
> I added a new disk and grew my raid6 md0 with the following command line
>
> sudo mdadm --grow --raid-devices=5
> --backup-file=/root/grow_md0.bkp_file --layout=normalise /dev/md0
>
> I got a response that stated that mdadm needed to backup 384K of data.
> However, when I checked after about 5min there was no backup file. Is
> this expected?
Yes.
When increasing the size of an array, the backup file is needed for a tiny
fraction of a second at the start.
When decreasing the size it is needed for a tiny fraction if a second at the
end.
When the size isn't changed it is needed for the entire time.
... unless you have a new kernel and a new mdadm, and then the backup file
isn't needed.
NeilBrown
>
> 386 > sudo ls /root
> <no files. so no output>
> 387 > sudo ls /root/grow_md0.bkp_file
> ls: cannot access /root/grow_md0.bkp_file: No such file or directory
>
> Ramesh
>
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next prev parent reply other threads:[~2014-10-13 1:39 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-13 1:26 mdadm --grow with --backup-file does not create backupfile? Ram Ramesh
2014-10-13 1:39 ` NeilBrown [this message]
2014-10-13 1:49 ` Ram Ramesh
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