Unable to boot with message not enough memory to relocate dom0 kernel on Red Hat Enterprise Linux 5

Solution Verified - Updated -

Environment

  • RHEL 5 32-bit
  • xen kernel

Issue

Booting a newly installed Red Hat Enterprise Linux 5 32-bit system fails

Resolution

  • Remove the crashkernel parameter in the kernel line from the grub bootloader
    Remove crashkernel=128M@16M from the line below
kernel /xen.gz-2.6.18-194.17.1.el5 crashkernel=128M@16M
  • Once successfully booted /etc/grub/grub.conf can be modified to make this change permanent
    Remove crashkernel=128M@16M from the section indicated below
title Red Hat Enterprise Linux Server (2.6.18-194.17.1.el5xen)
        root (hd0,0)
        kernel /xen.gz-2.6.18-194.17.1.el5 crashkernel=128M@16M
        module /vmlinuz-2.6.18-194.17.1.el5xen ro root=/dev/myvg/rootvol
        module /initrd-2.6.18-194.17.1.el5xen.img
  • If xen is not needed it may be worth installing a regular kernel.
# yum install kernel

Once this has been done modify grub to boot the newly installed kernel.

Diagnostic Steps

Boot screen will hang with the following message

Not enough memory to relocate dom0 kernel

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