RAID 10 Array unable to start

vgracanin · 08-25-2017, 03:33 AM

Hi,
I had an RAID 10 Array on 4x4TB drives. One of the drives failed recently and before I had a chance to get a new drive the PC died. Now I took those 3 working drives in a different machine and tried to assemble the array, however it is showing me that there is not enough drives to start the array.

mdadm --assemble --scan -v

Code:

mdadm: looking for devices for /dev/md/2
mdadm: /dev/sdd2 is not one of /dev/sdd3,/dev/sdc3,/dev/sdb3
mdadm: /dev/sdd1 is not one of /dev/sdd3,/dev/sdc3,/dev/sdb3
mdadm: /dev/sdd is not one of /dev/sdd3,/dev/sdc3,/dev/sdb3
mdadm: /dev/sdc2 is not one of /dev/sdd3,/dev/sdc3,/dev/sdb3
mdadm: /dev/sdc1 is not one of /dev/sdd3,/dev/sdc3,/dev/sdb3
mdadm: /dev/sdc is not one of /dev/sdd3,/dev/sdc3,/dev/sdb3
mdadm: /dev/sdb2 is not one of /dev/sdd3,/dev/sdc3,/dev/sdb3
mdadm: /dev/sdb1 is not one of /dev/sdd3,/dev/sdc3,/dev/sdb3
mdadm: /dev/sdb is not one of /dev/sdd3,/dev/sdc3,/dev/sdb3
mdadm: /dev/sda5 is not one of /dev/sdd3,/dev/sdc3,/dev/sdb3
mdadm: /dev/sda2 is not one of /dev/sdd3,/dev/sdc3,/dev/sdb3
mdadm: /dev/sda1 is not one of /dev/sdd3,/dev/sdc3,/dev/sdb3
mdadm: /dev/sda is not one of /dev/sdd3,/dev/sdc3,/dev/sdb3
mdadm: /dev/sr0 is not one of /dev/sdd3,/dev/sdc3,/dev/sdb3
mdadm: /dev/sdd3 is identified as a member of /dev/md/2, slot 3.
mdadm: /dev/sdc3 is identified as a member of /dev/md/2, slot 2.
mdadm: /dev/sdb3 is identified as a member of /dev/md/2, slot 32769.
mdadm: no uptodate device for slot 0 of /dev/md/2
mdadm: no uptodate device for slot 2 of /dev/md/2
mdadm: added /dev/sdd3 to /dev/md/2 as 3
mdadm: added /dev/sdc3 to /dev/md/2 as 2
mdadm: /dev/md/2 assembled from 2 drives - not enough to start the array.

mdadm --examine /dev/sdd3

Code:

    /dev/sdd3:
          Magic : a92b4efc
        Version : 1.2
    Feature Map : 0x0
     Array UUID : cd3892ab:b8aaa48a:20b5ab74:fddad0bb
           Name : Vault:2
    Creation Time : Sun Jun 12 08:36:56 2016
     Raid Level : raid10
    Raid Devices : 4
     Avail Dev Size : 7804393120 (3721.42 GiB 3995.85 GB)
     Array Size : 7804393088 (7442.85 GiB 7991.70 GB)
     Used Dev Size : 7804393088 (3721.42 GiB 3995.85 GB)
     Data Offset : 2048 sectors
     Super Offset : 8 sectors
     Unused Space : before=1968 sectors, after=32 sectors
          State : clean
     Device UUID : 8592628e:a97edfef:e6986718:30843c2a

     Update Time : Mon Jul 17 02:06:30 2017
       Checksum : fd90c0a - correct
         Events : 97672

         Layout : near=2
     Chunk Size : 64K

     Device Role : Active device 3
     Array State : ..AA ('A' == active, '.' == missing, 'R' == replacing)

mdadm --examine /dev/sdc3

Code:

    /dev/sdc3:
          Magic : a92b4efc
        Version : 1.2
    Feature Map : 0x0
     Array UUID : cd3892ab:b8aaa48a:20b5ab74:fddad0bb
           Name : Vault:2
    Creation Time : Sun Jun 12 08:36:56 2016
     Raid Level : raid10
     Raid Devices : 4

    Avail Dev Size : 7804393120 (3721.42 GiB 3995.85 GB)
     Array Size : 7804393088 (7442.85 GiB 7991.70 GB)
    Used Dev Size : 7804393088 (3721.42 GiB 3995.85 GB)
    Data Offset : 2048 sectors
    Super Offset : 8 sectors
    Unused Space : before=1968 sectors, after=32 sectors
          State : clean
    Device UUID : c37c9709:1f048b35:f3133e80:7d0d585d

    Update Time : Mon Jul 17 02:06:30 2017
       Checksum : 6bab8016 - correct
         Events : 97672

         Layout : near=2
     Chunk Size : 64K

    Device Role : Active device 2
    Array State : ..AA ('A' == active, '.' == missing, 'R' == replacing)

mdadm --examine /dev/sdb3

Code:

    /dev/sdb3:
          Magic : a92b4efc
        Version : 1.2
    Feature Map : 0x0
     Array UUID : cd3892ab:b8aaa48a:20b5ab74:fddad0bb
           Name : Vault:2
    Creation Time : Sun Jun 12 08:36:56 2016
     Raid Level : raid10
    Raid Devices : 4
  
    Avail Dev Size : 7804393120 (3721.42 GiB 3995.85 GB)
     Array Size : 7804393088 (7442.85 GiB 7991.70 GB)
    Used Dev Size : 7804393088 (3721.42 GiB 3995.85 GB)
    Data Offset : 2048 sectors
    Super Offset : 8 sectors
    Unused Space : before=1968 sectors, after=32 sectors
          State : clean
     Device UUID : 56d45c15:883a2c28:96b265ad:341003bb

     Update Time : Mon Jul 17 02:06:30 2017
       Checksum : f4e4bb8b - correct
         Events : 97672

         Layout : near=2
     Chunk Size : 64K

    Device Role : Active device 32769
    Array State : ..AA ('A' == active, '.' == missing, 'R' == replacing)

The only difference I can see is in the sdb3 is the "Device Role : Active device 32769"
Just to note that the RAID was on synology (xpenology).

Ztcoracat · 08-25-2017, 08:01 PM

Hi & Welcome to Linux Questions.

Please put output in Code Tags. It makes it easier for us to read and help you.

Looking at this:

Code:

mdadm: looking for devices for /dev/md/2
mdadm: /dev/sdd2 is not one of /dev/sdd3,/dev/sdc3,/dev/sdb3
mdadm: /dev/sdd1 is not one of /dev/sdd3,/dev/sdc3,/dev/sdb3
mdadm: /dev/sdd is not one of /dev/sdd3,/dev/sdc3,/dev/sdb3
mdadm: /dev/sdc2 is not one of /dev/sdd3,/dev/sdc3,/dev/sdb3
mdadm: /dev/sdc1 is not one of /dev/sdd3,/dev/sdc3,/dev/sdb3
mdadm: /dev/sdc is not one of /dev/sdd3,/dev/sdc3,/dev/sdb3
mdadm: /dev/sdb2 is not one of /dev/sdd3,/dev/sdc3,/dev/sdb3
mdadm: /dev/sdb1 is not one of /dev/sdd3,/dev/sdc3,/dev/sdb3
mdadm: /dev/sdb is not one of /dev/sdd3,/dev/sdc3,/dev/sdb3
mdadm: /dev/sda5 is not one of /dev/sdd3,/dev/sdc3,/dev/sdb3
mdadm: /dev/sda2 is not one of /dev/sdd3,/dev/sdc3,/dev/sdb3
mdadm: /dev/sda1 is not one of /dev/sdd3,/dev/sdc3,/dev/sdb3
mdadm: /dev/sda is not one of /dev/sdd3,/dev/sdc3,/dev/sdb3
mdadm: /dev/sr0 is not one of /dev/sdd3,/dev/sdc3,/dev/sdb3
mdadm: /dev/sdd3 is identified as a member of /dev/md/2, slot 3.
mdadm: /dev/sdc3 is identified as a member of /dev/md/2, slot 2.
mdadm: /dev/sdb3 is identified as a member of /dev/md/2, slot 32769.
mdadm: no uptodate device for slot 0 of /dev/md/2
mdadm: no uptodate device for slot 2 of /dev/md/2
mdadm: added /dev/sdd3 to /dev/md/2 as 3
mdadm: added /dev/sdc3 to /dev/md/2 as 2
mdadm: /dev/md/2 assembled from 2 drives - not enough to start the array.

Maybe this links will help?

https://unix.stackexchange.com/quest...tart-the-array
http://www.pc-freak.net/blog/way-to-...art-the-array/

Do you know which drive failed?

You will need a member that is good with RAID. Sorry that's not me, I'm still learning how to set it up.

jefro · 08-25-2017, 09:01 PM

I was trying to find a good web page on exactly your issue.

My understanding is you have to fail a device then work on it. On boot a raid does assemble by design. I have to admit that it looks like the drives are active. It may be that you should have numbered the drives out of the box and inserted them to slots that equate but I don't think that is needed.

vgracanin · 08-26-2017, 03:57 AM

I have 3 out of 4 drives that all look to be working and when I try to assemble them the third one is not added. They are in the same order as before.

Code:

/dev/sdd3 - Slot 3 
/dev/sdc3 - Slot 2
/dev/sdb3 - Slot 32769 (Should be Slot 1?)
/dev/sda3 - Missing/Dead (Should be Slot 0)

Even with one drive gone in RAID 10 i should be able to forcefully start it.

if I try to force it with "mdadm --assemble --force /dev/md0 /dev/sdb3 /dev/sdc3 /dev/sdd3" i still get the

Code:

mdadm: /dev/md/0 assembled from 2 drives - not enough to start the array.

and if use "mdadm --assemble --force /dev/disk/by-id/xx1 /dev/disk/by-id/xx2 /dev/disk/by-id/xx3 " I get that

Code:

/dev/disk/by-id/xx1 has no superblock - assembly aborted

vgracanin · 08-26-2017, 04:00 AM

Quote:

Originally Posted by Ztcoracat

Hi & Welcome to Linux Questions.

Please put output in Code Tags. It makes it easier for us to read and help you.

Thank you and sorry for the mess.

mitchd123 · 08-27-2017, 10:31 AM

long shot, but because you moved systems:

Double check that the raid modules are loading correctly.

lsmod |grep raid

or modprobe raid456

dmesg

Ztcoracat · 08-27-2017, 05:20 PM

Quote:

Originally Posted by vgracanin

Thank you and sorry for the mess.

You're Welcome.