From mboxrd@z Thu Jan 1 00:00:00 1970 From: Neil Brown Subject: Re: [PATCH 05/10] Add spares to raid0 array using takeover Date: Fri, 3 Dec 2010 14:52:25 +1100 Message-ID: <20101203145225.2acd7436@notabene.brown> References: <20101202080818.4639.38119.stgit@gklab-170-024.igk.intel.com> <20101202081920.4639.78609.stgit@gklab-170-024.igk.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20101202081920.4639.78609.stgit@gklab-170-024.igk.intel.com> Sender: linux-raid-owner@vger.kernel.org To: Adam Kwolek Cc: linux-raid@vger.kernel.org, dan.j.williams@intel.com, ed.ciechanowski@intel.com List-Id: linux-raid.ids On Thu, 02 Dec 2010 09:19:20 +0100 Adam Kwolek wrote: > Spares are used by Online Capacity Expansion to expand array. > To run expansion on raid0, spares have to be added to raid0 volume also. > Raid0 cannot have spares (no mdmon runs for raid0 array). > To do this, takeover to raid5 (and back) is used. mdmon runs temporary for raid5 and spare drives can be added to container. > > Signed-off-by: Adam Kwolek This is just wrong. If mdmon is running (maybe because some other array in the container needs it) then you add a spare to the container and send mdmon a metadata update to apply. If mdmon is not running, then you add a spare to the container and apply a metadata update directly in mdadm. There is no need to switch to raid5 and back just to add a spare. NeilBrown