Installation on IBM POWER systems with multiple Fibre Channel Disks ends in grub rescue mode

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Environment

SUSE Linux Enterprise Server 15
SUSE Linux Enterprise Server 15 Service Pack 1 (SLES 15 SP1)

Situation

The suggested partitioning scheme of SLES 15 installation puts the PReP and BOOT partitions on different disks if more than one disk is available. If these disks are Fibre Channel Disks, the GRUB boot-loader is not able to find the BOOT partition and the system cannot be booted. The installation ends with:

Welcome to GRUB!
error: no such device: <id>.
error: unknown filesystem.
Entering rescue mode...

grub rescue>

Resolution

The solution is to avoid multiple disk installation. When prompted to select the partition scheme, choose Guided Setup and verify that only one disk is selected for installation.

Cause

GRUB is unable to handle multiple FC disks at boot time. If the PREP and BOOT partitions are on different disks, the PREFIX variable will be set incorrectly and GRUB will not be able to load the necessary files from the BOOT partition.

Disclaimer

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