From mboxrd@z Thu Jan 1 00:00:00 1970 From: Neil Brown Subject: Re: Raid array is not automatically detected. Date: Thu, 19 Jul 2007 09:09:39 +1000 Message-ID: <18078.40371.650807.535202@notabene.brown> References: <4697E231.3070906@hp.com> <4698D4FC.2060100@tmr.com> <469B7E75.3030907@hp.com> <469B8D05.1080003@dgreaves.com> <469E2626.30204@hp.com> <469E35ED.3040500@dgreaves.com> <469E6267.9000107@tmr.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: message from Bill Davidsen on Wednesday July 18 Sender: linux-raid-owner@vger.kernel.org To: Bill Davidsen Cc: David Greaves , Bryan Christ , Justin Piszcz , linux-raid@vger.kernel.org List-Id: linux-raid.ids On Wednesday July 18, davidsen@tmr.com wrote: > David Greaves wrote: > > > > See where it says 'component' ? :) > > > > I wish mdadm --detail and --examine were just aliases and the output > > varied according to whether you looked at a component (eg /dev/sda1) > > or an md device (/dev/md0) > > > > I get that wrong *all* the time... > > Neil, if you will take that as a suggestion, you can take this as a > second. While I have learned to use the correct option most of the time, > this is a case where the software can make an unambiguous decision to > avoid the human having to stop and think which option is appropriate. The software cannot make an unambiguous decision. It is quite possible for one md device to be a component of another md device. In that case, --examine and --detail are both very meaningful and very different. If you have trouble remembering the difference, train yourself to use --query instead. I am willing to consider suggestions for improving the error message when -D or -E don't find what they expect. I am willing to add aliases that might make it easier to remember the difference (I confess that I chose 'detail' and 'examine' largely because they start with 'd' and 'e', to go with assemble, build, and create) I am willing to make --query more useful if anyone has any suggestions. But I am not willing to make --detail and --examine behave identically. NeilBrown