I need to upgrade my kernel on a RHEL 5 system to build with some experimental drivers. I have configured the kernel with module loading for LVM (dm_* modules). Once the initrd runs the /init script, the LVM mounting procedure is failing.

The drives are configured with LVM (including the root device) so during init, it mounts them and performs switchroot.

What can I do to understand why lvmscan is failing?

migrated from stackoverflow.com Jul 14 '14 at 19:26

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  • Did you build by calling make manually or did you use RHEL's build automation? Did you copy the configuration from the distribution's kernel? Did you rebuild the initrd? – Gilles Jul 15 '14 at 21:47
  • Latest kernel release candidate. Using make. Copied kernel config from distribution, rebuilt initrd. – user3275885 Jul 16 '14 at 13:24

So I figured out what the problem was: Red Hat's mkbldevs in the init script of the initrd.img was failing to make the block devices. Without any block devices LVM was not able to mount drives. I installed BusyBox and made a custom initrd and while in the shell I noticed that mkblkdevs called by the /bin/nash script didn't make /dev/sd*. I suppose you could manually use mknod to create the block devices but a search found that a kernel parameter was needed.

This is the kernel parameter:


You can set it in .config manually or browse to in under "General setup" in make menuconfig.

I can now boot a variety of kernels that I built.

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