[gentoo-user] Moving root filesystem to a new partition

[Alan E. Davis]

Can someone tell me what steps are necessary to move the / filesystem to a
new partition?  I recall someone helping me with this before, but cannot
find the email.  The oldest of three drives on my system had my / partition,
/dev/sdc1.  One day recently, that partition became inaccessable.  After
quickly installing Ubuntu on a different drive, that root partition
eventually showed up again.

So I've been able to boot Gentoo again off the separate /boot partition on
/dev/sda1.  I need to move that / partition.  I have several other
partitions mounted off this one, mainly as /usr and maybe /usr/local/, and
some storage partitions mounted to my home directory.

I copied the root (/) partition with the new partition at /dev/sdb5 mounted
as /newroot, using
    # cp -ax / /newroot

I checked that /proc, /dev, and /sys are there, and empty.  I recall there
are some other steps necessary.  I changed /etc/fstab, and the grub2
grub.cfg from ubuntu, the entry for this kernel.  The boot stalls at a
certain point.

May I ask what steps are necessary to do this?

Thank you,

Alan Davis