From mboxrd@z Thu Jan 1 00:00:00 1970 From: Neil Brown Subject: Re: Superblock V 1.2 Date: Tue, 16 Nov 2010 07:11:30 +1100 Message-ID: <20101116071130.3ed4871e@notabene.brown> References: <20101107191507.GA31052@cons.org> <20101107210852.GA77472@cons.org> <4CD71C77.4030400@anonymous.org.uk> <20101109163512.GA15649@cons.org> <4CD98021.2060501@anonymous.org.uk> <20101115121158.20e2e53e@notabene.brown> <20101115161646.GA38828@cons.org> <20101116064746.24aafe7b@notabene.brown> <20101115195220.GA27668@cons.org> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20101115195220.GA27668@cons.org> Sender: linux-raid-owner@vger.kernel.org To: Martin Cracauer Cc: John Robinson , linux-raid@vger.kernel.org List-Id: linux-raid.ids On Mon, 15 Nov 2010 14:52:20 -0500 Martin Cracauer wrote: > Neil Brown wrote on Tue, Nov 16, 2010 at 06:47:46AM +1100: > > On Mon, 15 Nov 2010 11:16:46 -0500 > > Martin Cracauer wrote: > > > > > Neil Brown wrote on Mon, Nov 15, 2010 at 12:11:58PM +1100: > > > > > > > > When mdadm does auto-assemble an array that doesn't obviously belong to this > > > > host, it tries to be careful and assembles it 'read-auto', which means that > > > > it is completely read-only until you try to write to the array. So no > > > > recovery or resync happens. > > > > Once you write to the array, md assumes that you are happy to have the array > > > > assembled on this device, and allows any resync etc to start. > > > > > > Speaking of which, are there any plans to do a true readonly mode? > > > > > > I missed that quite a few times. > > > > > > Martin > > > > In what does > > mdadm --readonly /dev/mdXX > > > > not meet your needs? > > (which is to say: I think there is a true readonly mode, but I've never > > seriously used it so don't know for certain that it is actually useful). > > Isn't that the mode that upgrades to read-write when you write? > No. NeilBrown