Booting into emergency mode after motherboard swap

[bluedalmatian]

I've swapped a motherboard on a CentOS system for a new one and now it won't boot. It starts to but then stops for ages at 'Reached target basic system' then goes to emergency shell with warnings about disks by-uuid not found. The system has 2 disks in a software raid 1 mirror both of which are present. There is another disk which has been removed but that was only used by an application for storing cctv recordings.

It says its generated a /run/initramfs/rdsosreport.txt file which seems to indicate systemd is aborting the startup due to not being able to find the disks.

Any idea why this is happening. I tried to look at the /etc/fstab file from the emergency shell but its not there!?

Thanks

[TrevorH]

Most likely the hardware is different and needs different drivers to be loaded in the initramfs.

Boot the last kernel on the list - should have 'rescue' in its name. That should boot on any hardware that was supported at the time the system was installed. From there, login as root, make a list of all the directories under /lib64/modules/ and pick the highest numbered one - current should be 3.10.0-957.12.2.el7.x86_64. If you do not currently have that kernel installed then the easy thing to do is just to install it. As part of the kernel install, yum will build a new initramfs for that kernel and include support for all the detected hardware at the time. Then you can boot that one.

If you do have that kernel installed then you will need to rebuild the initramfs for it. Either use yum reinstall kernel-3.10.0-957.12.2.el7.x86_64 or invoke dracut -f --kver=3.10.0-957.12.2.el7.x86_64

[bluedalmatian]

Yes that worked, thank you.