From mboxrd@z Thu Jan 1 00:00:00 1970 From: John Robinson Subject: Re: RAID6 data-check took almost 2 hours, clicking sounds, system unresponsive Date: Wed, 13 Apr 2011 12:58:10 +0100 Message-ID: <4DA58FD2.8040900@anonymous.org.uk> References: <323937.22450.qm@web65109.mail.ac2.yahoo.com> <4DA58194.4070403@anonymous.org.uk> <20110413211310.53f6026f@notabene.brown> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20110413211310.53f6026f@notabene.brown> Sender: linux-raid-owner@vger.kernel.org To: NeilBrown Cc: Gavin Flower , linux-raid@vger.kernel.org List-Id: linux-raid.ids On 13/04/2011 12:13, NeilBrown wrote: > On Wed, 13 Apr 2011 11:57:24 +0100 John Robinson > wrote: >> On 12/04/2011 22:30, Gavin Flower wrote: [...] >>> md0 : active raid6 sda3[0] sdb3[4] sdd3[3] sdc3[5](F) sde3[1] >>> 10751808 blocks level 6, 64k chunk, algorithm 2 [5/4] [UU_UU] >> >> This one I don't get: >> md0 : active raid6 sda3[0] sde3[1] sdd3[3] sdb3[4] sdc3[5](F) >> which ought to be UUUU_ again... >> >> Perhaps `mdadm -D /dev/md[0-2]` would make things clearer... > > This is actually more horrible than you imagine. It isn't really, I was asking for the mdadm -D output precisely to get the list of role and slot numbers, having noticed there was no slot 2 in Gavin's setup... [...] > As the current number is pretty much useless, I should probably change it to > the slot number, or an arbitrarily assigned larger number for spares. > This would be an incompatible change, but I very much doubt anyone uses the > numbers for what they actually are, so I doubt that would really matter. > > It has just never really got high on my list of priorities.... > > Lesson: Ignore the number in [] - it doesn't mean anything useful. It's not useless, it reflects the order in which devices were added to the array. Suggestion: Don't change the number in /proc/mdstat, just sort the devices by role (i.e. the same order as the UUUU_) instead of device node, and show spares at the end (as per your arbitrarily-assigned larger number, which this way you never have to display). Cheers, John.