From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tomasz Chmielewski Subject: Re: creating RAID-1 - in which direction will the sync be made? Date: Wed, 14 Jul 2010 15:48:39 +0200 Message-ID: <4C3DC037.1000802@wpkg.org> References: <4C3D8BA7.2020500@wpkg.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4C3D8BA7.2020500@wpkg.org> Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids On 14.07.2010 12:04, Tomasz Chmielewski wrote: > In which direction will the devices be synchronized, if I create a new RAID-1 array with an external bitmap? > > > Assuming I use this command line: > > mdadm --create /dev/md11 --level=1 --bitmap=/mnt/src/bitmap --raid-devices 2 /dev/storage/origin /dev/esata/copy > > > > Should I expect /dev/storage/origin being written to /dev/esata/copy? > > Or perhaps, /dev/esata/copy will be written onto /dev/storage/origin? > > > I couldn't find it explained in the fine manual, so perhaps creating an array with a missing device: > > mdadm --create /dev/md11 --level=1 --bitmap=/mnt/src/bitmap --raid-devices 2 /dev/storage/origin missing > > and adding a second device later will be safer... Looks like the first device in the command line will be synced onto the second. However, I'd like someone to confirm this. And that I should use "build" to sync the devices, otherwise, I'll write a superblock on each of them ;) -- Tomasz Chmielewski http://wpkg.org