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mdadm: raid1 mirror's spare won't activate

g'day Guys and girls!

So... I'm stumped... Basicly I had a faulty sata cable, ran the server degraded while getting a new cable, shut it down, installed the cable and booted it up and for some reason I can't get it to become active again..

Through numerous google searches on this problem I've come up with null, I've zeroed the super block, re-formatted, removed 512 KB of the beginning of the drive and still, she doesn't want to activate.. she syncs up with "Spare synchronizing" finishes and drops back in to the spare group..

I would recreate the array but this is my root drive..

Some one point me in the right direction -.-"

-Donny

Running Ubuntu Server, latest updates..

mdadm -D /dev/md0 shows...

Code:

root@LoM:~# mdadm -D /dev/md0

/dev/md0:

        Version : 1.2

  Creation Time : Sat Feb 11 14:56:56 2012

    Raid Level : raid1

    Array Size : 976758841 (931.51 GiB 1000.20 GB)

  Used Dev Size : 976758841 (931.51 GiB 1000.20 GB)

  Raid Devices : 2

  Total Devices : 2

    Persistence : Superblock is persistent



    Update Time : Thu Feb 16 08:46:56 2012

          State : clean, degraded

 Active Devices : 1

Working Devices : 2

 Failed Devices : 0

  Spare Devices : 1



          Name : LoM:0  (local to host LoM)

          UUID : 45a552f7:5e854deb:26a64954:01f3aaec

        Events : 116263



    Number  Major  Minor  RaidDevice State

      1      8        1        0      active sync  /dev/sda1

      1      0        0        1      removed



      2      8      17        -      spare  /dev/sdb1

cat /proc/mdstat shows...

Code:

root@LoM:~# cat /proc/mdstat

Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]

md0 : active raid1 sdb1[2](S) sda1[1]

      976758841 blocks super 1.2 [2/1] [U_]



unused devices: <none>

fdisk -l shows...

Code:

root@LoM:~# fdisk -l



Disk /dev/sda: 1000.2 GB, 1000204886016 bytes

255 heads, 63 sectors/track, 121601 cylinders, total 1953525168 sectors

Units = sectors of 1 * 512 = 512 bytes

Sector size (logical/physical): 512 bytes / 512 bytes

I/O size (minimum/optimal): 512 bytes / 512 bytes

Disk identifier: 0x0008e75b



  Device Boot      Start        End      Blocks  Id  System

/dev/sda1              63  1953520064  976760001  fd  Linux RAID autodetect



Disk /dev/sdb: 1000.2 GB, 1000204886016 bytes

255 heads, 63 sectors/track, 121601 cylinders, total 1953525168 sectors

Units = sectors of 1 * 512 = 512 bytes

Sector size (logical/physical): 512 bytes / 512 bytes

I/O size (minimum/optimal): 512 bytes / 512 bytes

Disk identifier: 0x00000000



  Device Boot      Start        End      Blocks  Id  System

/dev/sdb1              63  1953520064  976760001  fd  Linux RAID autodetect



Disk /dev/md0: 1000.2 GB, 1000201053184 bytes

2 heads, 4 sectors/track, 244189710 cylinders, total 1953517682 sectors

Units = sectors of 1 * 512 = 512 bytes

Sector size (logical/physical): 512 bytes / 512 bytes

I/O size (minimum/optimal): 512 bytes / 512 bytes

Disk identifier: 0x00000000



Disk /dev/md0 doesn't contain a valid partition table



Disk /dev/sdc: 3997 MB, 3997171712 bytes

213 heads, 47 sectors/track, 779 cylinders, total 7806976 sectors

Units = sectors of 1 * 512 = 512 bytes

Sector size (logical/physical): 512 bytes / 512 bytes

I/O size (minimum/optimal): 512 bytes / 512 bytes

Disk identifier: 0x000d3836



  Device Boot      Start        End      Blocks  Id  System

/dev/sdc1  *        2048    7804927    3901440  83  Linux

Have you tried to remove and re-add the the drive from the array? like:

Code:

mdadm /dev/md0 -r /dev/sdb1

mdadm /dev/md0 -a /dev/sdb1

Quote:

Originally Posted by romagnolo (Post 4604036)

Have you tried to remove and re-add the the drive from the array? like:

Code:

mdadm /dev/md0 -r /dev/sdb1

mdadm /dev/md0 -a /dev/sdb1

Thanks romagnolo for your reply

I've tried re-adding many time, with a combination of zeroing the super block, reformatting, dding away the first 512 KB of the hard drive and rebooting in case of some unknown cache

Recently I forced the array in to a 1 device mirror with

Code:

mdadm -G /dev/md0 --force -n 1

Rebooted and grew the array back to 2 with

Code:

mdadm -G /dev/md0 -n 2

Re-added the device with

Code:

mdadm --add /dev/md0 /dev/sdb1

waited the 2 hours for it to resync, the whole time showing

Code:

root@LoM:~# mdadm -D /dev/md0

/dev/md0:

        Version : 1.2

  Creation Time : Sat Feb 11 14:56:56 2012

    Raid Level : raid1

    Array Size : 976758841 (931.51 GiB 1000.20 GB)

  Used Dev Size : 976758841 (931.51 GiB 1000.20 GB)

  Raid Devices : 2

  Total Devices : 2

    Persistence : Superblock is persistent



    Update Time : Thu Feb 16 22:15:55 2012

          State : active, degraded, recovering

 Active Devices : 1

Working Devices : 2

 Failed Devices : 0

  Spare Devices : 1



 Rebuild Status : 0% complete



          Name : LoM:0  (local to host LoM)

          UUID : 45a552f7:5e854deb:26a64954:01f3aaec

        Events : 153215



    Number  Major  Minor  RaidDevice State

      1      8        1        0      active sync  /dev/sda1

      2      8      17        1      spare rebuilding  /dev/sdb1

and when its finished it drops in to spare and the original slot becomes 'Removed'

Have I missed something?

A more desperate bump...

I would recommend removing sdb1, zeroing the super block on sdb1 and then re-adding it. I've encountered re-adding problems in the past with a bad, but still readable, superblock.

Code:

mdadm /dev/md0 -r /dev/sdb1

mdadm --zero-superblock /dev/sdb1

mdadm /dev/md0 -a /dev/sdb1

So? any responses?

I ended up in the same situation, an active drive, a spare and a degraded array.... it's been a few months, were you able to figure out how to activate the spare?

g'day rleibman

It turns out in my situation the hard drive was failing but not reporting it back to SmartMon or mdadm, so mdadm failed silently giving no indication of why. Try with another hard drive if you have one and see if that activates, I gave the faulty 1 TB hard drive to a mate who partitioned it avoiding the faulty sector (Through trial and error) and to this day is running fine.

Good luck, Hall