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From: NeilBrown <neilb@suse.com>
To: Gandalf Corvotempesta <gandalf.corvotempesta@gmail.com>,
	Linux RAID Mailing List <linux-raid@vger.kernel.org>
Subject: Re: 3-way mirror to RAID-6
Date: Tue, 26 Dec 2017 08:53:27 +1100	[thread overview]
Message-ID: <87incu79uw.fsf@notabene.neil.brown.name> (raw)
In-Reply-To: <CAJH6TXg=uCQMmzSQPHC885naZj3cFOZx2oyx462mCBof9NeU+w@mail.gmail.com>

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On Mon, Dec 25 2017, Gandalf Corvotempesta wrote:

> Hi to all
> I have a server with a 3way mirror.
> As I have to increase the total available space, one solution would be to
> replace all disks with bigger ones, but this is expensive.
>
> Another solution would be to add just one disk and then reshape from
> RAID-1 to RAID-6
>
> Do you have any guide on how to do this reshape on a running array ?
> Thank you.

I suggest you add the new device with "mdadm --add", then try the
reshape with "mdadm --grow /dev/mdXXX --level=6 --raid-devices-4".

It might not work quite that easily - I think you need to first convert
the raid1 to a 2-way mirror, but that is easy enough

 mdadm --grow /dev/mdxxx --raid-devices=2

NeilBrown

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  reply	other threads:[~2017-12-25 21:53 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-12-25 19:36 3-way mirror to RAID-6 Gandalf Corvotempesta
2017-12-25 21:53 ` NeilBrown [this message]
2017-12-26 10:09   ` Wols Lists
2017-12-27 10:13   ` Gandalf Corvotempesta
2017-12-27 14:28     ` Phil Turmel
     [not found]       ` <CAJH6TXiqsd=Zs4t5qAEe19shJFgSAZ1W-95yT041H6OyLbKvfA@mail.gmail.com>
2017-12-28 12:34         ` Phil Turmel
2018-01-08 11:34           ` Gandalf Corvotempesta
2018-01-08 15:20             ` Wols Lists
2018-01-08 15:25               ` Gandalf Corvotempesta
2018-01-08 20:18                 ` Wol's lists

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