IBM Support

Systems with large memory or CPU configurations might not start completely

Flashes (Alerts)


Abstract

Systems with more than 16 TB of memory or more than 20 cores might not start completely. The system instead times out on a task and the system enters an emergency mode.

Content

Linux Releases Affected
Red Hat Enterprise Linux 8.x
Red Hat Enterprise Linux 9.x

IBM Systems Affected
All IBM POWER9, Power10, and Power11 systems that have memory size larger than 16 TB.
Some IBM POWER9, Power10, and Power11 systems that have more than 20 cores.
 
Symptoms
It is observed that systems with more than 16 TB of memory or more than 20 cores might not start completely and the system enters an emergency mode.
 
Workaround
Perform the following steps to resolve the issue:
1. Edit the /boot/grub2/grubenv file.
2. Find the line that begins with kernelopts=.
3. At the end of the identified line, add udev.children-max=2048.
4. Restart your system.

If the issue persists, revert the modifications that are done in the step 1-4. Make the following
updates to the /usr/lib/systemd/system/systemd-udev-trigger.service file:
1. In the file, comment out the following line:
     ExecStart=/usr/bin/udevadm trigger --type=devices --action=add
2. Add the following line after the line that is commented:
     ExecStart=/usr/bin/udevadm trigger --type=devices --subsystem-nomatch=memory --action=add
3. Restart your system.
 
Fix Outlook
IBM is working with Red Hat to release a fix for this issue. The fix would come as part of a future Red
Hat maintenance release. If a test fix is needed before the next corresponding Red Hat maintenance release, open a support ticket with Red Hat.

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Product Synonym

Red Hat Enterprise Linux 8.x
Red Hat Enterprise Linux 9.x

Document Information

Modified date:
29 July 2025

UID

ibm16209253