From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jes Sorensen Subject: Re: [PATCH] Add '--nodes' option in GROW mode Date: Thu, 24 Mar 2016 12:31:15 -0400 Message-ID: References: <56F13020.8020900@suse.com> <56F28046.9010801@suse.com> Mime-Version: 1.0 Content-Type: text/plain Return-path: In-Reply-To: <56F28046.9010801@suse.com> (Guoqing Jiang's message of "Wed, 23 Mar 2016 19:38:46 +0800") Sender: linux-raid-owner@vger.kernel.org To: Guoqing Jiang Cc: zhilong , linux-raid@vger.kernel.org List-Id: linux-raid.ids Guoqing Jiang writes: > On 03/23/2016 01:56 AM, Jes Sorensen wrote: >> zhilong writes: >>> Bug description: >>> # mdadm -Cv /dev/md0 --bitmap=clustered -l1 -n2 /dev/sdd /dev/sdb >>> --nodes=6 --assume-clean >>> # mdadm --grow /dev/md0 --bitmap=none >>> # mdadm --grow /dev/md0 --bitmap=clustered >>> -> cluster nodes would be changed to 4, here is my method to >>> resolve it. >>> # mdadm --grow /dev/md0 --bitmap=clustered --nodes=6 >>> >>> Patch: >>> >>> Cluster nodes is set 4 as default when switch bitmap from >>> none to clustered under GROW mode, so add '--nodes' >>> option in GROW mode. >>> >>> Signed-off-by: Zhilong Liu >>> --- >>> mdadm.c | 1 + >>> 1 file changed, 1 insertion(+) >> Hi, >> >> I have a question about this, since I simply do not have the knowledge >> about clustering to judge this approach. >> >> If you remove the bitmap, does that 'uncluster' the array? If not, > > Yes, remove the bitmap would 'uncluster' the array since leave() > will be called in kernel if switch the bitmap from 'clustered' to > 'none'. > >> shouldn't mdadm be fixed to not set #nodes to 4 when adding a clustered >> bitmap, if a number of cluster nodes is already present? > > The nodes is set 4 by default if the 'nodes' parameter is not specified, > And it could be overwrite if re-create the clustered bitmap. Thanks for the explanation, in that case I am fine with this. It does raise the issue whether specifying nodes shouldn't be a required argument rather than defaulting to a default of 4? Second, your patch was broken due to bad whitespace formatting, could you please send me a fresh one. Thanks, Jes