Replaced raid controller, raid config missing, server not booting

Question

My raid controller went bust, and my hoster OVH replaced it. They only offer hardware support, so after replacing the controller they left the machine in Rescue mode. When I put it in normal HD boot mode it won't boot up.

I had 2 drive software RAID1 setup which hosted the CentOS files.

And I had 4 drives software RAID10 which had my files.

In rescure mode I checked the array with:

cat /proc/mdstat
Personalities : [linear] [raid0] [raid1] [raid10] [raid6] [raid5] [raid4] [multipath] [faulty]
unused devices: <none>

and fdisk shows:

root@rescue:/mnt# fdisk -l

Disk /dev/ram0: 50 MiB, 52428800 bytes, 102400 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk /dev/ram1: 50 MiB, 52428800 bytes, 102400 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk /dev/ram2: 50 MiB, 52428800 bytes, 102400 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk /dev/ram3: 50 MiB, 52428800 bytes, 102400 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk /dev/ram4: 50 MiB, 52428800 bytes, 102400 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk /dev/ram5: 50 MiB, 52428800 bytes, 102400 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk /dev/ram6: 50 MiB, 52428800 bytes, 102400 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk /dev/ram7: 50 MiB, 52428800 bytes, 102400 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk /dev/ram8: 50 MiB, 52428800 bytes, 102400 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk /dev/ram9: 50 MiB, 52428800 bytes, 102400 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk /dev/ram10: 50 MiB, 52428800 bytes, 102400 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk /dev/ram11: 50 MiB, 52428800 bytes, 102400 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk /dev/ram12: 50 MiB, 52428800 bytes, 102400 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk /dev/ram13: 50 MiB, 52428800 bytes, 102400 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk /dev/ram14: 50 MiB, 52428800 bytes, 102400 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk /dev/ram15: 50 MiB, 52428800 bytes, 102400 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk /dev/sda: 447.1 GiB, 480103981056 bytes, 937703088 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt
Disk identifier: 7D555295-0B10-4D4B-9A17-6EEFBBA3CB99

Device         Start       End   Sectors   Size Type
/dev/sda1       2048   1048575   1046528   511M EFI System
/dev/sda2    1048576  42006527  40957952  19.5G Linux RAID
/dev/sda3   42006528 936644607 894638080 426.6G Linux RAID
/dev/sda4  936644608 937691135   1046528   511M Linux swap

Disk /dev/sdb: 447.1 GiB, 480103981056 bytes, 937703088 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt
Disk identifier: 63C7B674-C42F-4F25-A610-F72AFACD5134

Device         Start       End   Sectors   Size Type
/dev/sdb1       2048   1048575   1046528   511M EFI System
/dev/sdb2    1048576  42006527  40957952  19.5G Linux RAID
/dev/sdb3   42006528 936644607 894638080 426.6G Linux RAID
/dev/sdb4  936644608 937691135   1046528   511M Linux swap

Disk /dev/sde: 10.9 TiB, 12000138625024 bytes, 23437770752 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt
Disk identifier: 6FDD3C33-DE0C-4DF0-9554-677826FC34F6

Device     Start         End     Sectors  Size Type
/dev/sde1   2048 23437770718 23437768671 10.9T Linux RAID

Disk /dev/sdf: 10.9 TiB, 12000138625024 bytes, 23437770752 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt
Disk identifier: 433686A7-5E89-4AE4-8BF8-3AAC9E9BDD82

Device     Start         End     Sectors  Size Type
/dev/sdf1   2048 23437770718 23437768671 10.9T Linux RAID

Disk /dev/sdd: 10.9 TiB, 12000138625024 bytes, 23437770752 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt
Disk identifier: 638E004E-798E-4C77-BEFD-5FF5AADEA855

Device     Start         End     Sectors  Size Type
/dev/sdd1   2048 23437770718 23437768671 10.9T Linux RAID

Disk /dev/sdc: 10.9 TiB, 12000138625024 bytes, 23437770752 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt
Disk identifier: 42B1E5D7-697E-4BD5-8B9B-86B664022E25

Device     Start         End     Sectors  Size Type
/dev/sdc1   2048 23437770718 23437768671 10.9T Linux RAID

All the disks are intact, so all the files are still there. But just the raid setup isn't there anymore. How can I recreate my RAID1 and RAID10 setup so that I can boot into CentOS again?

My hoster offers 0 support, OVH is really terrible.

Should I simply use mdadm to create a new array? I'm worried I'm breaking something. I saw some warnings, so I didn't press continue:

root@rescue:/mnt# mdadm --create /dev/md127 --level raid10 --name data --raid-disks 4 /dev/sdc1 /dev/sdd1 /dev/sde1 /dev/sdf1
mdadm: /dev/sdc1 appears to be part of a raid array:
       level=raid10 devices=4 ctime=Mon Oct  7 12:02:49 2019
mdadm: partition table exists on /dev/sdc1 but will be lost or
       meaningless after creating array
mdadm: /dev/sdd1 appears to be part of a raid array:
       level=raid10 devices=4 ctime=Mon Oct  7 12:02:49 2019
mdadm: partition table exists on /dev/sdd1 but will be lost or
       meaningless after creating array
mdadm: /dev/sde1 appears to be part of a raid array:
       level=raid10 devices=4 ctime=Mon Oct  7 12:02:49 2019
mdadm: partition table exists on /dev/sde1 but will be lost or
       meaningless after creating array
mdadm: /dev/sdf1 appears to be part of a raid array:
       level=raid10 devices=4 ctime=Mon Oct  7 12:02:49 2019
mdadm: partition table exists on /dev/sdf1 but will be lost or
       meaningless after creating array
Continue creating array?

Before you go any further - do you have backups? Also, have you tried to `assemble` the existing array instead of `create`? `create` will make a *new* RAID array which is what you don't want! `mdadm --assemble` — Bert, Oct 22 '19 at 16:11
are you talking about your software based RAID of Hardware based RAID controller? if there is something happened with the hardware based controller, then replacing it with a new controller, dosen't have to make any corruption to your data. unless if they have changed the location of the hard drives from their original bay numbers. — Zareh Kasparian, Oct 23 '19 at 20:23

Replaced raid controller, raid config missing, server not booting

0 Answers0