From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chris Eddington Subject: Re: Raid5 assemble after dual sata port failure Date: Fri, 09 Nov 2007 13:23:49 -0800 Message-ID: <4734CFE5.8070305@synplicity.com> References: <47321FDF.8060207@synplicity.com> <4732E5F0.7080805@dgreaves.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4732E5F0.7080805@dgreaves.com> Sender: linux-raid-owner@vger.kernel.org To: David Greaves Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids Thanks David. I've had cable/port failures in the past and after re-adding the drive, the order changed - I'm not sure why, but I noticed it sometime ago but don't remember the exact order. My initial attempt to assemble, it came up with only two drives in the array. Then I tried assembling with --force and that brought up 3 of the drives. At that point I thought I was good, so I tried mount /dev/md0 and it failed. Would that have written to the disk? I'm using XFS. After that, I tried assembling with different drive orders on the command line, i.e. mdadm -Av --force /dev/md0 /dev/sda1, ... thinking that the order might not be right. At the moment I can't access the machine, but I'll try fsck -n and send you the other info later this evening. Many thanks, Chris David Greaves wrote: > Chris Eddington wrote: > >> Hi, >> > Hi > >> While on vacation I had one SATA port/cable fail, and then four hours >> later a second one fail. After fixing/moving the SATA ports, I can >> reboot and all drives seem to be OK now, but when assembled it won't >> recognize the filesystem. >> > > That's unusual - if the array comes back then you should be OK. > In general if two devices fail then there is a real data loss risk. > However if the drives are good and there was just a cable glitch, then unless > you're unlucky it's usually fsck fixable. > > I see > mdadm: /dev/md0 has been started with 3 drives (out of 4). > > which means it's now up and running. > > And: > sda1 Events : 0.4880374 > sdb1 Events : 0.4880374 > sdc1 Events : 0.4857597 > sdd1 Events : 0.4880374 > > so sdc1 is way out of date... we'll add/resync that when everything else is working. > > but: > >> After futzing around with assemble options >> like --force and disk order I couldn't get it to work. >> > > Let me check... what commands did you use? Just 'assemble' - which doesn't care > about disk order - or did you try to re-'create' the array - which does care > about disk order and leads us down a different path... > err, scratch that: > >> Creation Time : Sun Nov 5 14:25:01 2006 >> > OK, it was created a year ago... so you did use assemble. > > > It is slightly odd to see that the drive order is: > /dev/mapper/sda1 > /dev/mapper/sdb1 > /dev/mapper/sdd1 > /dev/mapper/sdc1 > Usually people just create them in order. > > > Have you done any fsck's that involve a write? > > What filesystem are you running? What does your 'fsck -n' (readonly) report? > > Also, please report the results of: > cat /proc/mdadm > mdadm -D /dev/md0 > cat /etc/mdadm.conf > > > David > >