Booting LPARs with very large amounts of CPU and memory assigned, the system may exit to the emergency shell

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Environment

SUSE Linux Enterprise Server 12 Service Pack 3 (SLES 12 SP3) (ppc64le)

SUSE Linux Enterprise Server 12 Service Pack 4 (SLES 12 SP4) (ppc64le)

SUSE Linux Enterprise Server 12 Service Pack 5 (SLES 12 SP5) (ppc64le)

SUSE Linux Enterprise Server 15 (ppc64le)

SUSE Linux Enterprise Server 15 Service Pack 1 (SLES 15 SP1) (ppc64le)
SUSE Linux Enterprise Server 15 Service Pack 2 (SLES 15 SP2) (ppc64le)
SUSE Linux Enterprise Server 15 Service Pack 3 (SLES 15 SP3) (ppc64le)
SUSE Linux Enterprise Server 15 Service Pack 4 (SLES 15 SP4) (ppc64le)

Situation

When booting logical partitions (LPARs) with large amounts of CPU and memory assigned, the system may time-out and exit to the emergency shell, showing messages similar to the following:

You are in emergency mode. After logging in, type "journalctl -xb" to view
system logs, "systemctl reboot" to reboot, "systemctl default" or ^D to
try again to boot into default mode.
Give root password for maintenance
(or press Control-D to continue):

The system should show messages prior to this that complain of a timeout waiting for devices, specifically the device for the /home filesystem.

Resolution

The system can usually be booted simply by entering the root password and pressing Ctrl-D or typing "exit" at the shell prompt. In some cases, it may be necessary to enter the command "lvm lvchange -a y system" before exiting the emergency mode shell.

A more-permanent workaround is to edit the file /etc/default/grub and append "systemd.default_timeout_start_sec=1800" to the GRUB_CMDLINE_LINUX_DEFAULT entry, for example:

GRUB_CMDLINE_LINUX_DEFAULT="resume=/dev/sdXX splash=silent quiet crashkernel=226M-:113M showopts systemd.default_timeout_start_sec=1800"

For a system with more than 32TB main memory please use "systemd.default_timeout_start_sec=3600" in the GRUB_CMDLINE_LINUX_DEFAULT entry.

After making this change it is required to run "grub2-mkconfig -o /boot/grub2/grub.cfg" to update the boot loader configuration.

Additional Information

Note that SUSE is working closely with IBM to release a fix for this issue which should be released as part of a future SLES maintenance release. For additional information see Bug # 1103094.

Disclaimer

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