From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Zafman Subject: Re: OSD replacement feature Date: Fri, 20 Nov 2015 09:54:50 -0800 Message-ID: <564F5E6A.5050407@redhat.com> References: <564E04F9.20607@dachary.org> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mx1.redhat.com ([209.132.183.28]:49136 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934659AbbKTRyw (ORCPT ); Fri, 20 Nov 2015 12:54:52 -0500 In-Reply-To: Sender: ceph-devel-owner@vger.kernel.org List-ID: To: Sage Weil , Wei-Chung Cheng Cc: Ceph Development There are two reasons for having a ceph-disk replace feature. 1. To simplify the steps required to replace a disk 2. To allow a disk to be replaced proactively without causing any data movement. So keeping the osd id the same is required and is what motivated the feature for me. David On 11/20/15 3:38 AM, Sage Weil wrote: > On Fri, 20 Nov 2015, Wei-Chung Cheng wrote: >> Hi Loic and cephers, >> >> Sure, I have time to help (comment) on this feature replace a disk. >> This is a useful feature to handle disk failure :p >> >> An simple step is described on http://tracker.ceph.com/issues/13732 : >> 1. set noout flag - if the broken osd is primary osd, could we handle well? >> 2. stop osd daemon and we need to wait the osd actually down. (or >> maybe use deactivate option with ceph-disk) >> >> these two above step seems OK. >> about handle crush map, should we remove the broken osd out? >> If we do that, why we set noout flag? It still trigger re-balance >> after we remove osd from crushmap. > Right--I think you generally want to do either one or the other: > > 1) mark osd out, leave failed disk in place. or, replace with new disk > that re-uses the same osd id. > > or, > > 2) remove osd from crush map. replace with new disk (which gets new osd > id). > > I think re-using the osd id is awkward currently, so doing 1 and replacing > the disk ends up moving data twice. > > sage > -- > To unsubscribe from this list: send the line "unsubscribe ceph-devel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html