From mboxrd@z Thu Jan 1 00:00:00 1970 From: Phillip Susi Subject: Re: [PATCH 00/21] [RFC] Btrfs: restriper Date: Tue, 15 Nov 2011 09:33:14 -0500 Message-ID: <4EC2782A.3050005@cfl.rr.com> References: <1314129722-31601-1-git-send-email-idryomov@gmail.com> <4EC1AB52.2070805@cfl.rr.com> <20111115092224.GA8597@zambezi.lan> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Cc: linux-btrfs@vger.kernel.org To: Ilya Dryomov Return-path: In-Reply-To: <20111115092224.GA8597@zambezi.lan> List-ID: On 11/15/2011 4:22 AM, Ilya Dryomov wrote: > Restriper won't let you do raid1 -> dup transition because dup is only > allowed for a single-spindle FS, so you'll end up with error "btrfs: > unable to start restripe ...". > > There is no way to prioritize disks during restripe. To get dup back > you'll have to convert everything to single, remove the second drive and > then convert metadata from single to dup. So there is no way to put a disk into read only mode and prevent allocations of new chunks there? It seems like both of these limitations are highly undesirable when trying to recover from a failing disk. You don't want any more data being written to the failing disk while you are trying to remove it, and you certainly don't want to drop back to a single copy of data that is then written to the failing disk.