From mboxrd@z Thu Jan 1 00:00:00 1970 From: Roberto Nunnari Subject: Re: replacing drives Date: Wed, 08 May 2013 18:05:32 +0200 Message-ID: <518A77CC.2040001@supsi.ch> References: <517A8EB5.8080100@supsi.ch> <20130426155347.GA9928@cthulhu.home.robinhill.me.uk> <5183E592.6020409@supsi.ch> <20130507075340.GA25772@cthulhu.home.robinhill.me.uk> <518A5EF5.5090808@supsi.ch> <20130508151019.GA20347@cthulhu.home.robinhill.me.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20130508151019.GA20347@cthulhu.home.robinhill.me.uk> Sender: linux-raid-owner@vger.kernel.org To: Roberto Nunnari , "linux-raid@vger.kernel.org" List-Id: linux-raid.ids Robin Hill wrote: > On Wed May 08, 2013 at 04:19:33PM +0200, Roberto Nunnari wrote: > >> Robin Hill wrote: >>> On Fri May 03, 2013 at 06:28:02PM +0200, Roberto Nunnari wrote: >>> >>>> Robin Hill wrote: >>>>> The safest option would be: >>>>> - add in the new disks >>>>> - partition to at least the same size as your existing partitions (they >>>>> can be larger) >>>>> - add the new partitions into the arrays (they'll go in as spares) >>>>> - grow the arrays to 4 members (this avoids any loss of redundancy) >>>>> - wait for the resync to complete >>>>> - install grub/lilo/syslinux to the new disks >>>>> - fail and remove the old disk partitions from the arrays >>>>> - shrink the arrays back down to 2 members >>>>> - remove the old disks >>>>> >>>>> Then, if you're keeping the same number of partitions but increasing the >>>>> size: >>>> Ok.. got here. >>>> >>>>> - grow the arrays to fill the partitions >>>>> - grow the filesystems to fill the arrays >>>> Now the scary part.. so.. here I believe I should give the following >>>> commands: >>>> >>>> mdadm --grow /dev/md0 --size=max >>>> mdadm --grow /dev/md1 --size=max >>>> mdadm --grow /dev/md2 --size=max >>>> >>> Yep, that's right. Make sure they've actually grown to the correct size >>> before you progress though - I have had one occasion where using >>> --size=max actually ended up shrinking the array and I had to manually >>> work out the size to use in order to recover. That was using an older >>> version of mdadm though, and I've not seen it happen since. >>> >>>> and after that >>>> >>>> fsck /dev/md0 >>>> fsck /dev/md1 >>>> fsck /dev/md2 >>>> >>> You'll need 'fsck -f' here to force it to run. >> humm.. as /dev/md0 is mounted on / I probably should boot from a cd, and >> run fsck and resize2fs from there.. maybe using UUIDs, right? >> > You can just skip the fsck and run resize2fs - it'll work fine on a > mounted filesystem. It'll probably be safer to do it offline though. > > Cheers, > Robin I'd rather stay on the safe side.. how do I assemble the array if I boot from a cd? something like: mdadm --scan --assemble --uuid=a26bf396:31389f83:0df1722d:f404fe4c would to the job and let me with a /dev/mdX I will be able to work with (fsck and resize2fs)? Thank you. Robi