Keith Williams said:
for me, downloading configs and data then uploading
where possible is definitely the fastest and easiest option
BitFolk has the huge advantage that you can retain the IP address of
the previous VPS. Where that's not the case, and you don't want to
update assorted stuff to point to the new one, an in-place upgrade is
possible, but it is a serious pain and you're looking at about well
over an hour of downtime.
This is the edited highlights of what I had to do following another
guide, so *do* *not* treat this as a complete recipe!
(Make dpkg aware of the new architecture)
dpkg --add-architecture amd64
(update the package database - you should get access to i386 and amd64
versions of everything)
apt-get update
(install the 64-bit kernel)
apt-get install linux-image-amd64:amd64
(and get the three files you need amd64 versions of, which you can't
get and install via apt)
apt-get --download-only install dpkg:amd64 tar:amd64 apt:amd64
(reboot)
(install those three)
dpkg --install /var/cache/apt/archives/tar_1.29b-1.1_amd64.deb
etc
(edit grub.cfg and run grub-update to boot into 64-bit kernel)
(reboot)
(install more amd64 versions)
dpkg --get-selections | grep :i386 | sed -e s/:i386/:amd64/ | dpkg
--set-selections
apt-get update
apt-get upgrade
(sort some of the problems that left)
apt -o Debug::pkgProblemResolver=1 -f install
(see how many i386 packages are left)
apt list --installed | grep i386
(manually install amd64 versions for those where only an i386 version
is installed
apt-get install zip
(and many more)
(remove the i386 versions of the kernel)
apt-get remove linux-image-686-pae linux-image-4.9.0-8-686-pae
(edit grub.cfg again and update-grub)
(reboot, with crossed fingers)
(repeat the see how many i386 versions left, remove / replace with
amd64 ones loop until there aren't any, with crossed fingers when it
comes to removing the i386 version of glibc towards the very end of
this)
(remove the i386 architecture)
(reboot, with crossed fingers)
.. and it works. But it would have been much quicker to just create a
new amd64 VPS and copy the configuration of the old one over.
Ian