Raid 0 disk outside

Question

by mistake I run a fdisk /dev/sdb and then w to a raid 0 member, I see a message like the disk is now outside the raid but I ignored that and keep working on the machine. Then I make a reboot and pfff no system.

I booted the machine from a USB and when I run mdadm -E /dev/sda I can see the raid details with a disk failed.

/dev/sda:
          Magic : Intel Raid ISM Cfg Sig.
        Version : 1.0.00
    Orig Family : 4f3cdac1
         Family : 4f3cdac1
     Generation : 00000822
     Attributes : All supported
           UUID : f97ee5a6:3b369876:9d9d52a0:32dc2de7
       Checksum : e58e948c correct
    MPB Sectors : 1
          Disks : 2
   RAID Devices : 1

  Disk00 Serial : 60L012651018DCHC
          State : active
             Id : 00000000
    Usable Size : 500113672 (238.47 GiB 256.06 GB)

[OEMRAID0]:
           UUID : 37adbe48:51eed222:1ec4fe1c:4a6f936c
     RAID Level : 0
        Members : 2
          Slots : [U_]
    Failed disk : 1
      This Slot : 0
     Array Size : 1000226816 (476.95 GiB 512.12 GB)
   Per Dev Size : 500113672 (238.47 GiB 256.06 GB)
  Sector Offset : 0
    Num Stripes : 1953568
     Chunk Size : 128 KiB
       Reserved : 0
  Migrate State : idle
      Map State : failed
    Dirty State : clean

  Disk01 Serial : L0126510196FHC:0
          State : active
             Id : ffffffff
    Usable Size : 500113672 (238.47 GiB 256.06 GB)

Then I try to re-add the disk to the array with mdadm --manage /dev/md0 -a /dev/sdb and the disk is added but the raid is not working.

/dev/sdb:
          Magic : Intel Raid ISM Cfg Sig.
        Version : 1.0.00
    Orig Family : 00000000
         Family : 75517a2b
     Generation : 00000001
     Attributes : All supported
           UUID : 00000000:00000000:00000000:00000000
       Checksum : eaa2f456 correct
    MPB Sectors : 1
          Disks : 1
   RAID Devices : 0

  Disk00 Serial : 60L0126510196FHC
          State : spare
             Id : 01000000
    Usable Size : 500115982 (238.47 GiB 256.06 GB)

    Disk Serial : 60L0126510196FHC
          State : spare
             Id : 01000000
    Usable Size : 500115982 (238.47 GiB 256.06 GB)

What can I do?

score 2 · Accepted Answer · answered Feb 10 '19 at 07:26

First of all: After a RAID misconfiguration, don’t do anything that writes to the disks until you’ve read https://raid.wiki.kernel.org/index.php/Linux_Raid#When_Things_Go_Wrogn.

But as you probaby know, RAID0 is a special case of RAID, in that it by its very definition is not a redundant array of independent disks. Instead it’s a risky way of speeding up disk I/O operations, with (at least) twice the physical failure risk and an increased risk - as you saw - of admninistrative mistakes.

Unfortunately, the most likely answer to your question is ”Recreate your array from scratch and recover your data from your latest backups.”

I tried in many ways with no success... so i restore a previous backup. Thanks for your reply. — mijailr, Feb 11 '19 at 19:50

Raid 0 disk outside

1 Answers1