start_udev

start_udev

[rich turner]

i am trying to understand exactly what start_udev does.

running fc3 with / on lvm. the initrd created by fc3 works fine and
i realize using fc3's mkinitrd would solve the problem but i want to
understand what is happending.

i have created my own initrd that basically creates the root filesystem
device and exits to allow the kernel to mount the / filesystem. i do not
mount /dev in the initrd or start_udev in the initrd. this all works
fine.

when the initrd exits it executes init (rc.sysinit). everything is fine
until it comes to a line in rc.sysinit to start_udev. then i lose the
devices /dev/vg0/rootlv and checking the root filesystem fails because
there is no device by that name. i still have /dev/dm-255 but my
_real_device_names_ are gone. i could change /etc/fstab to use
/dev/dm-255 but i prefer to use _real_names_

i see that one of the things that start_udev does is mount a tmpfs on
/dev.

does start_udev mount /dev if it already is not mounted?

what is strange is that with the initrd created by fc3 (which does mount
and start udev in the initrd), after running start_udev the
_real_device_names_ for my logical volumes are still there.

does start_udev populate the new /dev with old entries found in the /dev
populated by the initrd?

thanks in advance for any help



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Re: start_udev

[Greg KH]

On Tue, Dec 14, 2004 at 05:19:07PM -0800, rich turner wrote:
> i am trying to understand exactly what start_udev does.

It scans sysfs and creates "fake" udev events based on the dev files
found in sysfs.  I recommend using udevstart instead as it's much faster
and handles the "which order to create things in" issues which it sounds
like you need.

As for your other questions, I think a fedora mailing list would be
better, as those issues are specific to your distro.

thanks,

greg k-h


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