On Tue, Dec 3, 2013 at 12:06 AM, Canek Peláez Valdés <can...@gmail.com> wrote: > On Mon, Dec 2, 2013 at 10:34 PM, Jc García <jyo.gar...@gmail.com> wrote: >> 2013/12/2 William Kenworthy <bi...@iinet.net.au> >>> >>> You are looking far too deep .... >>> >>> >>> just rsync -avP to /newusr >> >> +1 >> I have done this more or less the same way >>> >>> reboot to livecd >>> >>> rsync again with --delete to update ... takes a only few seconds this >>> time - minimal downtime :) >>> mv /usr /oldusr >>> mv /newusr /usr >>> reboot >> >> >> Let's make this thread more interesting, would it be possible to do >> this without a reboot? ie: going single user mode, kill anything that >> might still be running from usr, umount /usr, mount it to /mnt, rsync >> -avP to usr, going again into runlevel 3 or 5. >> Obviously not possible if running systemd. > > I'm not so sure it's not possible. Perhaps it's even easier.
So, yeah, I think it's easier with systemd. You just: 1. systemctl isolate emergency.target 2. log in again (all the normal gettys are killed with the above command) 3. rsync -PvasHA /usr/ /newusr/ 4. mv /usr /oldusr # mv is on /bin, so no problems here 5. mv /newusr /usr 6. rm -rf /oldusr (to make sure nothing uses it anymore) 7. systemctl isolate multi-user.target 8. You have your system again. I did this on a minimal QEMU virtual machine. However I think it should work with even the most complex setups, as long as your initramfs has the necessary tools, which is really easy with dracut. Regards. -- Canek Peláez Valdés Posgrado en Ciencia e Ingeniería de la Computación Universidad Nacional Autónoma de México
