Arch Linux

gbetsis

Member

Registered: 2018-12-10

Posts: 1

Booting issues (I am using RAID1 mdadm array)

Hi everyone. I have an issue with a system using two HDDs in RAID1 (mdadm).
While the two disks are connected to the motherboard, the system can boot successfully. Whenever I disconnect one of them and then trying to boot, I am getting an error about not finding device with UUID=…

The error I am getting when booting with only one of the disks, is the following:

:: running early hook [udev]
Starting version 239
:: running hook [udev]
:: Triggering uevents…
Waiting 10 seconds for device /dev/disk/by-uuid/dfb9aa03-24da-4b38-979c-0dfc95a5dbfe…
ERROR: device ‘UUID=dfb9aa03-24da-4b38-979c-0dfc95a5dbfe’ not found. Skipping fsck.
::mounting ‘UUID=dfb9aa03-24da-4b38-979c-0dfc95a5dbfe’ on real root
mount: /new_root: can’t find UUID=dfb9aa03-24da-4b38-979c-0dfc95a5dbfe.
You are now being dropped into an emergency shell.

When booting with both HDDs, system is booting properly. Here is the output of lsblk:

[root@cloud ~]# lsblk -o NAME,UUID
NAME      UUID
sda       
├─sda1    d7d3267f-f9c5-4a80-974b-f58f82af392a
├─sda2    f2b276bc-76e1-7768-1095-f3ef718f54e3
│ └─md126 dfb9aa03-24da-4b38-979c-0dfc95a5dbfe
└─sda3    eebf1062-1e49-ea83-a47d-cba344cdda8c
  └─md127 43005680-b164-4d2d-9e77-71f4e129098d
sdb       
├─sdb1    1457fec3-136d-4707-9379-4754f95fffbc
├─sdb2    f2b276bc-76e1-7768-1095-f3ef718f54e3
│ └─md126 dfb9aa03-24da-4b38-979c-0dfc95a5dbfe
└─sdb3    eebf1062-1e49-ea83-a47d-cba344cdda8c
  └─md127 43005680-b164-4d2d-9e77-71f4e129098d
sr0       
[root@cloud ~]#

I am using the simplest grub configuration, to troubleshoot the issue.

[root@cloud ~]# cat /boot/grub/grub.cfg 
set timeout=1

set root='mduuid/f2b276bc76e177681095f3ef718f54e3'

menuentry 'Arch Linux' {
 linux /boot/vmlinuz-linux root=UUID=dfb9aa03-24da-4b38-979c-0dfc95a5dbfe rw
 initrd /boot/initramfs-linux.img
}
[root@cloud ~]#

The issue also happens when using the auto generated grub config using grub-mkconfig.

Here is the mdadm UUIDs:

[root@cloud ~]# mdadm --examine /dev/sda2
/dev/sda2:
          Magic : a92b4efc
        Version : 1.2
    Feature Map : 0x0
     Array UUID : f2b276bc:76e17768:1095f3ef:718f54e3
           Name : archiso:osRaid
  Creation Time : Tue Dec  4 15:22:59 2018
     Raid Level : raid1
   Raid Devices : 2

 Avail Dev Size : 41910272 (19.98 GiB 21.46 GB)
     Array Size : 20955136 (19.98 GiB 21.46 GB)
    Data Offset : 32768 sectors
   Super Offset : 8 sectors
   Unused Space : before=32616 sectors, after=0 sectors
          State : clean
    Device UUID : 2deea591:1174a28a:1b92dea0:5fb88a67

    Update Time : Mon Dec 10 11:37:29 2018
  Bad Block Log : 512 entries available at offset 136 sectors
       Checksum : 8756a6f7 - correct
         Events : 17


   Device Role : Active device 0
   Array State : AA ('A' == active, '.' == missing, 'R' == replacing)
[root@cloud ~]# mdadm --examine /dev/sdb2
/dev/sdb2:
          Magic : a92b4efc
        Version : 1.2
    Feature Map : 0x0
     Array UUID : f2b276bc:76e17768:1095f3ef:718f54e3
           Name : archiso:osRaid
  Creation Time : Tue Dec  4 15:22:59 2018
     Raid Level : raid1
   Raid Devices : 2

 Avail Dev Size : 41910272 (19.98 GiB 21.46 GB)
     Array Size : 20955136 (19.98 GiB 21.46 GB)
    Data Offset : 32768 sectors
   Super Offset : 8 sectors
   Unused Space : before=32616 sectors, after=0 sectors
          State : clean
    Device UUID : 4c7ae891:7be8b595:5c31cccd:7bf513db

    Update Time : Mon Dec 10 11:37:29 2018
  Bad Block Log : 512 entries available at offset 136 sectors
       Checksum : 332383df - correct
         Events : 17


   Device Role : Active device 1
   Array State : AA ('A' == active, '.' == missing, 'R' == replacing)
[root@cloud ~]#

And here is the mount command:

[root@cloud ~]# mount
...
/dev/md126 on / type ext4 (rw,relatime,stripe=256)
...
/dev/md127 on /usr/share/webapps type ext4 (rw,relatime,stripe=256)
...

[root@cloud ~]# cat /proc/mdstat
Personalities : [raid1] 
md126 : active raid1 sda2[0] sdb2[1]
      20955136 blocks super 1.2 [2/2] [UU]
      
md127 : active raid1 sda3[0] sdb3[1]
      220997760 blocks super 1.2 [2/2] [UU]
      bitmap: 2/2 pages [8KB], 65536KB chunk

unused devices: <none>
[root@cloud ~]# mdadm -Esv
ARRAY /dev/md/osRaid  level=raid1 metadata=1.2 num-devices=2 UUID=f2b276bc:76e17768:1095f3ef:718f54e3 name=archiso:osRaid
   devices=/dev/sdb2,/dev/sda2
ARRAY /dev/md/dataRaid  level=raid1 metadata=1.2 num-devices=2 UUID=eebf1062:1e49ea83:a47dcba3:44cdda8c name=archiso:dataRaid
   devices=/dev/sdb3,/dev/sda3
[root@cloud ~]#

Last edited by gbetsis (2018-12-10 10:14:08)