[clug] Kernel without initramfs

Daniel Pittman daniel at rimspace.net
Tue Mar 24 23:27:26 GMT 2009

David Cottrill <cottrill.david at gmail.com> writes:

> I'm working at getting a P2 300MHz to boot in a reasonable time - the
> initramfs runtime on a generic kernel is about 2 minutes.

That, as others have noted, is excessively slow: I booted the generic
Debian kernel, and the generic Ubuntu kernel, on a slower machine in a
fraction of that time — literally, in fact, about fifteen seconds from
boot loader to running off disk.

You might want to set 'modules=dep' rather than 'modules=most' to reduce
the volume of the initrd, though, if you blame the size of that...

> To fix this I've built and will be rebuilding a custom kernel with all
> the required modules built in.
> What I've done - lsmod from the generic kernel, made sure all modules
> listed got included in the kernel in my custom version.
> The remaining problem: After finding all my devices (including my hard disk)
> the boot sequence fails to mount the root partition (local).
> The first and last error message is:
> VFS: can't mount (insert disk label or /dev/hda1 or /dev/sda1 or anything
> else here) or block (0,0)
> Please append a correct root=... Choose from the following partitions:
> There isn't a list of partitions to choose from so I guess it is the problem
> is in the part of the kernel that recognises partitions but my most recent
> build included almost all of the partition options so I'm a little bit
> mystified.
> Any suggestions?

Use an initrd that provides busybox, so you can break out of a failed
boot and inspect the system to identify where the problem comes from?


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