System does not boot anymore after extending root filesystem

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Environment

SUSE Linux Enterprise Server 12 - System Z (s390x)

Situation

After adding a disk volume to the volume group of the root filesystem, or in case of btrfs, to the root filesystem itself, the root filesystem cannot be mounted on next IPL. Systemd endlessly prints messages similar to A start job is running for dev-disk...ab12cdef.device (60s / no limit).

Resolution

After adding the additional disk and before restarting the system, grub2 and the initrd need be updated so it will set the additional disk volume online. The following commands will do that:

mkinitrd
update-bootloader --reinit
update-bootloader --refresh

In case the system was rebooted without recreating the grub2 bootloader and the initrd, the rescue system can be used to fix the issue.

Cause

Grub2 and the initrd will only set disk devices online that are needed to mount the root filesystem to avoid long waiting times when a large amount of disks are visible to the system. Thus, both need to be updated to contain the information that an additional disk is required. This affects only filesystems mandatory to start the installed system, for filesystems that get mounted afterwards this is not necessary.

Additional Information

In case system was rebooted, kindly check TID 000019686 - System does not boot after extending btrfs root filesystem

Disclaimer

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