Raid array missing device. Missing raid member shows individ

[erik02]

I have followed the add disk instructions and appartently made an error. I have been searching for the past day or so and I am coming up with a lot of great information but none that has helped me resolve my issue.

I have array MD0 showign up with 1 device. 1 of my 4TB drives is showing up as a single disk. I am not concerned about data loss or starting over.
Firmware Version 5big2 fvdw-sl 16.1
Kernel: Linux 3.14.2 #14 PREEMPT Sun Jan 17 20:40:19 CET 2016

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root@fvdwsl-base:/ # mdadm --detail /dev/md0
/dev/md0:
        Version : 01.00.03
  Creation Time : Thu Dec 30 08:25:36 2027
     Raid Level : raid1
     Array Size : 3904113508 (3723.25 GiB 3997.81 GB)
    Device Size : 7808227016
   Raid Devices : 2
  Total Devices : 1
Preferred Minor : 0
    Persistence : Superblock is persistent

    Update Time : Thu Dec 30 11:15:30 2027
          State : clean, degraded
 Active Devices : 1
Working Devices : 1
 Failed Devices : 0
  Spare Devices : 0

           Name : 0
           UUID : fd37bff0:b58f8678:23313ccf:63bb9ed2
         Events : 94

    Number   Major   Minor   RaidDevice State
       0       0        0        0      removed
       1       8       56        1      active sync   /dev/sde8

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root@fvdwsl-base:/ # cat /etc/mdadm.conf
CREATE owner=root group=root mode=0666 auto=yes metadata=1.0
PROGRAM /usr/bin/mdadm-events
DEVICE /dev/sd* /dev/sd*
ARRAY /dev/md0 level=raid1 num-devices=2 name=0 UUID=fd37bff0:b58f8678:23313ccf:63bb9ed2
root@fvdwsl-base:/ #

I rebooted after 15% of syncronization was completed.

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Every 60s: cat /proc/mdstat                                                                                                                         2027-12-30 11:24:34

Personalities : [linear] [raid0] [raid1] [raid10] [raid6] [raid5] [raid4]
md0 : active raid1 sde8[1]
      3904113508 blocks super 1.0 [2/1] [_U]

unused devices: <none>

I have attached an image of how it shows in the webconsole. I have not been able to figure out why /dev/sdd shows as a single disk and is not a member of md0. I deleted all partitions when I began the process and they are in FD00.

[Jocko]

Hi erik02,

It seems you tried to build a raid in 2 steps and I assume you use this command

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mdadm --create /dev/md0 --level=1 --raid-devices=2 missing /dev/sde8

And then save raid conf in mdadm.conf
(Note it seems you edited manually this file or mdadm.0 as this line is wrong

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DEVICE /dev/sd* /dev/sd*

Should be

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DEVICE /dev/sd* /dev/se*

)

If you reboot at this step it is logical that sdd8 is not in the raid and your screen capture is ok.
The raid waits you add the 2d device to synchronize fully md0

If you tried to build md0 in 2 steps, I assume you want backup data from sdd8 to the new raid0 :scratch and then you can move the data (by moving share or on the user side by using samba access)
If it is not the case, build in 2 steps was useless and now you need to add sdd8.

So read this part of the tutorial : you need to unmount sdd8 and add it with this command

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root@Sargas:/ # mdadm --add /dev/md0 /dev/sdc8
mdadm: added /dev/sdc8
root@Sargas:/ # mdadm --detail /dev/md0
/dev/md0:
        Version : 1.0
  Creation Time : Sun Jan 29 18:14:30 2017
     Raid Level : raid1
     Array Size : 78148544 (74.53 GiB 80.02 GB)
  Used Dev Size : 78148544 (74.53 GiB 80.02 GB)
   Raid Devices : 2
  Total Devices : 2
    Persistence : Superblock is persistent

    Update Time : Sun Jan 29 18:20:39 2017
          State : clean, degraded, recovering
 Active Devices : 1
Working Devices : 2
 Failed Devices : 0
  Spare Devices : 1

 Rebuild Status : 0% complete

           Name : Sargas.local:0  (local to host Sargas.local)
           UUID : 52225552:e247224f:8da30d68:00215707
         Events : 148

    Number   Major   Minor   RaidDevice State
       2       8        8        0      spare rebuilding   /dev/sdc8
       1       8       72        1      active sync   /dev/sdd8
root@Sargas:/ # cat /proc/mdstat
Personalities : [linear] [raid0] [raid1] [raid10] [raid6] [raid5] [raid4]
md0 : active raid1 sdc8[2] sdd8[1]
      78148544 blocks super 1.0 [2/1] [_U]
      [>....................]  recovery =  1.4% (1143040/78148544) finish=22.4min speed=57152K/sec

unused devices: <none>


if it is ok, you do not need to wait recovery end and you can reboot the NAS;

Then sdd8(VOL-D) should be not displayed in the disk setup menu

NOte: Please to use BBCode 'code' when you paste output (read them is more easy)

[erik02]

Thank you for finding my error! Everything is working at this time and the array is synchronizing. I'm going to attempt to do this again with a smaller array for repitition. I greatly appreciate you taking the time and give me this info!