From mboxrd@z Thu Jan 1 00:00:00 1970 From: "John Stoffel" Subject: Re: Linux Plumbers MD BOF discussion notes Date: Wed, 4 Oct 2017 14:03:00 -0400 Message-ID: <22997.8788.365049.748860@quad.stoffel.home> References: <20170915142737.qafwl3vgl6vhfi5q@kernel.org> <871sn78pzt.fsf@notabene.neil.brown.name> <874ls0s7un.fsf@notabene.neil.brown.name> <87lgkr3fgj.fsf@notabene.neil.brown.name> <619758c0-9ca4-c25d-c61b-f411b095041d@intel.com> <076977d4-dfae-e8d3-7606-29e838f422ec@intel.com> <20171004173059.GB3181@lazy.lzy> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20171004173059.GB3181@lazy.lzy> Sender: linux-raid-owner@vger.kernel.org To: Piergiorgio Sartor Cc: Artur Paszkiewicz , NeilBrown , Mikael Abrahamsson , linux-raid@vger.kernel.org List-Id: linux-raid.ids >>>>> "Piergiorgio" == Piergiorgio Sartor writes: Piergiorgio> On Wed, Oct 04, 2017 at 01:23:02PM +0200, Artur Paszkiewicz wrote: >> On 10/04/2017 01:02 PM, Artur Paszkiewicz wrote: >> > Applications like mdadm can use this to hide/unhide their component >> > devices. >> >> And here is an example patch for mdadm. It adds options to manually hide >> or unhide the component devices: >> >> mdadm --hide-components /dev/md0 >> mdadm --unhide-components /dev/md0 Piergiorgio> This seems to me already quite sensible. >> >> And an option for mdadm.conf that automatically hides the array's member >> disks when assembling and when new disks are added: >> >> ARRAY /dev/md/0 metadata=1.2 UUID=c2c4f8c6:cd775924:9cb2cc62:88fa45bd >> name=linux-ns31:0 hide-components=yes >> >> Hidden disks (by mdadm --hide-components or by config) should unhide >> when the array is stopped or disks are removed. It only works for whole >> devices, not partitions. Piergiorgio> Well, this, on the other hands, it makes it not really Piergiorgio> useful. Yeah, this totally doesn't work or scale. If you're using partitions (why would you not?) as raid devices, even on a whole disk, you now limit yourself.