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From: Adam Borowski <kilobyte@angband.pl>
To: Subscription Account <4subsacct+btrfs@gmail.com>
Cc: btrfs <linux-btrfs@vger.kernel.org>
Subject: Re: Raid1 won't mount degraded
Date: Mon, 30 Jan 2017 02:49:23 +0100	[thread overview]
Message-ID: <20170130014923.42rma3b5oirquog6@angband.pl> (raw)
In-Reply-To: <CAHMMHbfUkrpN4+pJwAgRP_LqezC1uY8w0p5e-P1LDRUW06KyMw@mail.gmail.com>

On Sun, Jan 29, 2017 at 08:26:54PM -0500, Subscription Account wrote:
> On Sun, Jan 29, 2017 at 3:16 PM, Adam Borowski <kilobyte@angband.pl> wrote:
> > On Sun, Jan 29, 2017 at 08:12:56AM -0500, Subscription Account wrote:
> >> [ 2506.816795] BTRFS: missing devices(1) exceeds the limit(0),
> >> writeable mount is not allowed
> >>
> >> In the read-only mode I am not able to add a new device or replace :(.
> >> Please help.
> >
> > A known problem; you can mount rw degraded only once, if you don't fix the
> > degradation somehow (by adding a device or converting down), you can't mount
> > rw again.
> 
> Uh oh! I wish I know that I only had one shot :(.

No data is actually lost, it was raid1, it's raid1+single now.  The mount
check is naive and in this case wrong.

> > If you know how to build a kernel, here's a crude patch.
> 
> I am feeling a little lucky because I still have the other disk and I
> am assuming if I remove my current disk and put the other disk in, I
> would be able to mount it once again?

Not sure if that's a good idea if the copies are out of sync.

> Also, since I have couple times already tried btrfs repair etc, can I
> trust the current disk anyways?
> 
> if I get into issue again, I would definitely use the patch to
> recompile the kernel and thanks a lot for the same.

No, the patch doesn't prevent the issue.  It lets you recover -- ie, it
should help in the situation you're in right now.


Meow!
-- 
Autotools hint: to do a zx-spectrum build on a pdp11 host, type:
  ./configure --host=zx-spectrum --build=pdp11

  reply	other threads:[~2017-01-30  1:49 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-01-29 13:12 Raid1 won't mount degraded Subscription Account
2017-01-29 15:37 ` Subscription Account
2017-01-29 15:57   ` Lakshmipathi.G
2017-01-29 16:02     ` Subscription Account
2017-01-29 20:16 ` Adam Borowski
2017-01-30  1:26   ` Subscription Account
2017-01-30  1:49     ` Adam Borowski [this message]
2017-01-30  1:53       ` Subscription Account

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