From: Phillip Susi <psusi@cfl.rr.com>
To: Alexandre Oliva <oliva@lsd.ic.unicamp.br>
Cc: linux-btrfs@vger.kernel.org
Subject: Re: Don't prevent removal of devices that break raid reqs
Date: Mon, 05 Dec 2011 16:20:51 -0500 [thread overview]
Message-ID: <4EDD35B3.5050303@cfl.rr.com> (raw)
In-Reply-To: <orvcqrpycf.fsf@livre.localdomain>
On 11/10/2011 2:32 PM, Alexandre Oliva wrote:
> Instead of preventing the removal of devices that would render existing
> raid10 or raid1 impossible, warn but go ahead with it; the rebalancing
> code is smart enough to use different block group types.
>
> Should the refusal remain, so that we'd only proceed with a
> newly-introduced --force option or so?
I just thought of something. When adding the second device, balance
converts DUP to RAID1 automatically, and it is the RAID1 that prevents
removing the second disk. What if the chunks were left with both the
DUP and RAID1 flags set? That way if you explicitly requested raid1,
then it won't let you accidentally drop below two disks, but if it were
auto promoted from DUP, then going back to DUP is ok.
prev parent reply other threads:[~2011-12-05 21:20 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-10 19:32 Don't prevent removal of devices that break raid reqs Alexandre Oliva
2011-11-11 2:21 ` Chris Mason
2011-11-15 9:37 ` Ilya Dryomov
2011-11-16 1:10 ` Chris Mason
2011-11-16 3:21 ` Alexandre Oliva
2011-11-19 10:10 ` Alexandre Oliva
2011-12-05 21:20 ` Phillip Susi [this message]
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