Re: disk order problem in a raid 10 array

[Xavier Brochard <xavier@alternatif.org>]

Le samedi 19 mars 2011 00:20:39 NeilBrown, vous avez écrit :
> On Fri, 18 Mar 2011 23:50:18 +0100 Xavier Brochard <xavier@alternatif.org>
> > Le vendredi 18 mars 2011 23:22:51, NeilBrown  écrivait :
> > > On Fri, 18 Mar 2011 21:12:49 +0100 Xavier Brochard
> > > > Le vendredi 18 mars 2011 18:22:34 hansbkk@gmail.com, vous avez écrit :
> > > > > On Fri, Mar 18, 2011 at 9:49 PM, Xavier Brochard
> > > > > <xavier@alternatif.org>
> > > > 
> > > > wrote:
> > > > > > disk order is mixed between each boot - even with live-cd.
> > > > > > is that normal?
> > > > > 
> > > > > If nothing is changing and the order is swapping really every boot,
> > > > > then IMO that is odd.
> > > > 
> > > > nothing has changed, except kernel minor version
> > > 
> > > Yet you don't tell us what the kernel minor version changed from or to.
> > 
> > Previously it was ubuntu 2.6.32-27-server or 2.6.32-28-server and now it
> > is ubuntu 2.6.32-29.58-server 2.6.32.28+drm33.13
> > 
> > > That may not be important, but it might and you obviously don't know
> > > which. It is always better to give too much information rather than
> > > not enough.

> > 
> > Here's full output of mdadm --examine /dev/sd[cdefg]1
> > As you can see, disks sdc, sdd and sde claims to be different, is it a
> > problem?
> 
> Where all of these outputs collected at the same time?

yes

> They seem
> inconsistent.

> In particular, sdc1 has a higher 'events' number than the others (154 vs
> 102) yet an earlier Update Time.  It also thinks that the array is
> completely failed.

When I removed that disk (sdc is number 2) and another one (I tried with 
different disks), all other disks display (with mdadm -E):
0	Active
1	Active
2	Active
3 	Active
4	Spare

But when I removed that disk (#2) and #0, it start to recover and all other 
disks display (with mdadm -E):
0	Removed
1	Active
2	Faulty removed
3	Active
4	Spare
That looks coherent for me, now.

> So I suspect that device is badly confused and you probably want to zero
> it's metadata ... but don't do that too hastily.
> 
> All the other devices think the array is working correctly with a full
> compliment of devices.  However there is no device which claims to
> be "RaidDevice 2" - except sdc1 and it is obviously confused..
> 
> The device name listed in the table at the end of --examine output.
> It is the name that the device had when the metadata was last written.  And
> device names can change on reboot.
> The fact that the names don't line up suggest that the metadata hasn't been
> written since the last reboot - so presumably you aren't really using the
> array.(???)
> 
> [the newer 1.x metadata format doesn't try to record the names of devices
> in the superblock so it doesn't result in some of this confusion).
> 
> 
> Based on your earlier email, it would appear that the device discovery for
> some of your devices is happening in parallel at boot time, so or ordering
> could be random - each time you boot you get a different order.  This will
> not confuse md or mdadm - they look at the content of the devices rather
> than the name.
> If you want a definitive name for each device, it might be a good idea to
> look in /dev/disk/by-path or /dev/disk/by-id and use names from there.
> 
> Could you please sent a complete output of:
> 
>    cat /proc/mdstat
>    mdadm -D /dev/md0
>    mdadm -E /dev/sd?1
> 
> all collected at the same time.  Then I will suggest if there is any action
> you should take to repair anything.

Here it is, thankyou for you help

mdstat:
=====
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] 
[raid10] 
md0 : inactive sdb1[2](S) sdf1[4](S) sdd1[3](S) sdc1[1](S) sde1[0](S)
      2441919680 blocks
       
unused devices: <none>
====
obviously, mdadm -D /dev/md0 output nothing

mdadm -E /dev/sd?1
====
/dev/sdb1:
          Magic : a92b4efc
        Version : 0.90.00
           UUID : b784237b:5a021f4d:4cf004e3:2cb521cf
  Creation Time : Sun Jan  2 16:41:45 2011
     Raid Level : raid10
  Used Dev Size : 488383936 (465.76 GiB 500.11 GB)
     Array Size : 976767872 (931.52 GiB 1000.21 GB)
   Raid Devices : 4
  Total Devices : 5
Preferred Minor : 0

    Update Time : Wed Mar 16 09:50:03 2011
          State : clean
 Active Devices : 1
Working Devices : 1
 Failed Devices : 2
  Spare Devices : 0
       Checksum : ec151590 - correct
         Events : 154

         Layout : near=2
     Chunk Size : 64K

      Number   Major   Minor   RaidDevice State
this     2       8       65        2      active sync   /dev/sde1

   0     0       0        0        0      removed
   1     1       0        0        1      faulty removed
   2     2       8       65        2      active sync   /dev/sde1
   3     3       0        0        3      faulty removed
/dev/sdc1:
          Magic : a92b4efc
        Version : 0.90.00
           UUID : b784237b:5a021f4d:4cf004e3:2cb521cf
  Creation Time : Sun Jan  2 16:41:45 2011
     Raid Level : raid10
  Used Dev Size : 488383936 (465.76 GiB 500.11 GB)
     Array Size : 976767872 (931.52 GiB 1000.21 GB)
   Raid Devices : 4
  Total Devices : 3
Preferred Minor : 0

    Update Time : Fri Mar 18 16:37:45 2011
          State : clean
 Active Devices : 2
Working Devices : 3
 Failed Devices : 1
  Spare Devices : 1
       Checksum : ec181672 - correct
         Events : 107

         Layout : near=2
     Chunk Size : 64K

      Number   Major   Minor   RaidDevice State
this     1       8       17        1      active sync   /dev/sdb1

   0     0       0        0        0      removed
   1     1       8       17        1      active sync   /dev/sdb1
   2     2       0        0        2      faulty removed
   3     3       8       49        3      active sync   /dev/sdd1
   4     4       8       33        4      spare   /dev/sdc1
/dev/sdd1:
          Magic : a92b4efc
        Version : 0.90.00
           UUID : b784237b:5a021f4d:4cf004e3:2cb521cf
  Creation Time : Sun Jan  2 16:41:45 2011
     Raid Level : raid10
  Used Dev Size : 488383936 (465.76 GiB 500.11 GB)
     Array Size : 976767872 (931.52 GiB 1000.21 GB)
   Raid Devices : 4
  Total Devices : 3
Preferred Minor : 0

    Update Time : Fri Mar 18 16:37:45 2011
          State : clean
 Active Devices : 2
Working Devices : 3
 Failed Devices : 1
  Spare Devices : 1
       Checksum : ec181696 - correct
         Events : 107

         Layout : near=2
     Chunk Size : 64K

      Number   Major   Minor   RaidDevice State
this     3       8       49        3      active sync   /dev/sdd1

   0     0       0        0        0      removed
   1     1       8       17        1      active sync   /dev/sdb1
   2     2       0        0        2      faulty removed
   3     3       8       49        3      active sync   /dev/sdd1
   4     4       8       33        4      spare   /dev/sdc1
/dev/sde1:
          Magic : a92b4efc
        Version : 0.90.00
           UUID : b784237b:5a021f4d:4cf004e3:2cb521cf
  Creation Time : Sun Jan  2 16:41:45 2011
     Raid Level : raid10
  Used Dev Size : 488383936 (465.76 GiB 500.11 GB)
     Array Size : 976767872 (931.52 GiB 1000.21 GB)
   Raid Devices : 4
  Total Devices : 5
Preferred Minor : 0

    Update Time : Wed Mar 16 07:43:45 2011
          State : clean
 Active Devices : 4
Working Devices : 5
 Failed Devices : 0
  Spare Devices : 1
       Checksum : ec14f740 - correct
         Events : 102

         Layout : near=2
     Chunk Size : 64K

      Number   Major   Minor   RaidDevice State
this     0       8       33        0      active sync   /dev/sdc1

   0     0       8       33        0      active sync   /dev/sdc1
   1     1       8       49        1      active sync   /dev/sdd1
   2     2       8       65        2      active sync   /dev/sde1
   3     3       8       81        3      active sync   /dev/sdf1
   4     4       8       97        4      spare
/dev/sdf1:
          Magic : a92b4efc
        Version : 0.90.00
           UUID : b784237b:5a021f4d:4cf004e3:2cb521cf
  Creation Time : Sun Jan  2 16:41:45 2011
     Raid Level : raid10
  Used Dev Size : 488383936 (465.76 GiB 500.11 GB)
     Array Size : 976767872 (931.52 GiB 1000.21 GB)
   Raid Devices : 4
  Total Devices : 3
Preferred Minor : 0

    Update Time : Fri Mar 18 16:37:45 2011
          State : clean
 Active Devices : 2
Working Devices : 3
 Failed Devices : 1
  Spare Devices : 1
       Checksum : ec181682 - correct
         Events : 107

         Layout : near=2
     Chunk Size : 64K

      Number   Major   Minor   RaidDevice State
this     4       8       33        4      spare   /dev/sdc1

   0     0       0        0        0      removed
   1     1       8       17        1      active sync   /dev/sdb1
   2     2       0        0        2      faulty removed
   3     3       8       49        3      active sync   /dev/sdd1
   4     4       8       33        4      spare   /dev/sdc1
====



Xavier
xavier@alternatif.org - 09 54 06 16 26
--
To unsubscribe from this list: send the line "unsubscribe linux-raid" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html