Since my development server got into Kernel Panic, I ended up reinstalling it. I thought instead of manually installing everything again, I will get a more alike configuration to the production server if I restore a full server backup from production to development using my cloud backup solution.
So the OS is Ubuntu 16.04 on both servers, and although the restoration went well, as I was changing SSH configuration and rebooted the development server I discovered a new important thing that needs to be fixed - Disk partition UUIDs were wrong, as the filesystem was restored from a different physical device.
I was able to boot into GRUB (don't know what version, couldn't find how to check that), but in my searches found no use for that, but instead came to believe that I need to reinstall GRUB. I successfully booted into the Rescue kernel on the development server and was carefully trying to understand and learn how to do this GRUB reinstall properly.
The best resource I found was this StackExchange post, but as my attempts didn't match my expectations, I realised that this post is not about RAID1, which is what I have. Furthermore, I believe that I have a dedicated GRUB partition.
I am unable to mount /dev/sda# and /dev/sdb# partitions, I get a message like mount: unknown filesystem type 'linux_raid_member'.
So what I have (I think) understood from the fdisk -l output below is that:
- /dev/sda1-3 are the main partitions for the OS
- /dev/sdb1-3 are the mirror RAID partitions for sda
- /dev/md127 is the Multi-Device partition that represents the RAID1 that consists of sda and sdb
- /dev/md126 I am guessing is the dedicated GRUB partition as I have noticed people make 1 MB partitions for that
Output of fdisk -l in Rescue 64bit 4.x-Kernel:
Disk /dev/ram0: 80 MiB, 83886080 bytes, 163840 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: 80 MiB, 83886080 bytes, 163840 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: 80 MiB, 83886080 bytes, 163840 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: 80 MiB, 83886080 bytes, 163840 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: 80 MiB, 83886080 bytes, 163840 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: 80 MiB, 83886080 bytes, 163840 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: 80 MiB, 83886080 bytes, 163840 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: 80 MiB, 83886080 bytes, 163840 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: 80 MiB, 83886080 bytes, 163840 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: 80 MiB, 83886080 bytes, 163840 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: 80 MiB, 83886080 bytes, 163840 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: 80 MiB, 83886080 bytes, 163840 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: 80 MiB, 83886080 bytes, 163840 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: 80 MiB, 83886080 bytes, 163840 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: 80 MiB, 83886080 bytes, 163840 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: 80 MiB, 83886080 bytes, 163840 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/loop0: 77 MiB, 80732160 bytes, 157680 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 /dev/sda: 223.6 GiB, 240057409536 bytes, 468862128 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
Disklabel type: dos
Disk identifier: 0xcdb133c6
Device Boot Start End Sectors Size Id Type
/dev/sda1 2048 2050047 2048000 1000M fd Linux raid autodetect
/dev/sda2 2050048 10049535 7999488 3.8G 82 Linux swap / Solaris
/dev/sda3 10049536 468860927 458811392 218.8G fd Linux raid autodetect
Disk /dev/sdb: 223.6 GiB, 240057409536 bytes, 468862128 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
Disklabel type: dos
Disk identifier: 0x41d48153
Device Boot Start End Sectors Size Id Type
/dev/sdb1 2048 2050047 2048000 1000M fd Linux raid autodetect
/dev/sdb2 2050048 10049535 7999488 3.8G 82 Linux swap / Solaris
/dev/sdb3 10049536 468860927 458811392 218.8G fd Linux raid autodetect
Disk /dev/md127: 218.8 GiB, 234911236096 bytes, 458811008 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 /dev/md126: 1000 MiB, 1048510464 bytes, 2047872 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
I am reluctant to simply mount /dev/md126 and install GRUB using that because I see other guides doing something with the mdam utility and handling all these various partitions - not nearly as simple and short as without RAID.
This guide for RAID1 does not mention a dedicated GRUB partition and does not even run the GRUB install, so I doubt it suits my situation?
So how should I properly handle this situation and set GRUB and RAID1 back in place on this development server (cloned from a separate production server)? Thank you for your answers, much appreciated!
