rsync on root vs package reinstall
This is a followup of what I believe to be three open issues re the following query on this forum:
rsync boot disk dirs to exclude
https://ask.fedoraproject.org/en/ques...
Because of my inexperience, one of my replies on that query became mis-positioned, which caused that webpage to be confusing. I'm hoping for responses from several people on this followup query. Issues:
(1) Suppose that:
a. My boot drive is (device = sda) and my docking station houses a backup hard drive (device = sdc).
b. I have already used a recent version of Fedora22 Live to install the (full) Fedora22 on (device = sdc), making sdc bootable.
c. I want to maintain sdc as a full backup (i.e. a functional "clone") in case sda goes bad, totally relying on periodic rsync's of the sda-root against sdc to keep sdc current.
d. I want to be able to both boot the backup from the docker (position sdc) or replace the original boot disk with the backup, booting the backup in (position sda).
e. I want to TOTALLY AVOID having to reinstall any packages.
My Fedora 22 boot drive has the following directory structure:
.autorelabel, bin, boot, .config, dev, etc, home, lib, lib32, lib64, lost+found, media, mnt, opt, proc, root, run, sbin, srv, sys, tmp, usr, var
My tentative list of directories to exclude is:
/dev, /home, /media, /mnt, /proc, /run/media, /sys, /tmp, /var/lock, /var/run
/home is excluded because I rsync it separately. Under the assumptions of issue (1), I REQUEST DISCUSSION OF DIRECTORIES TO EXCLUDE.
(2) In my Linux-inexperience, and focusing on supposition (1)d above, I have speculated that /etc/fstab and /boot/grub2/grub.cfg may need special handling. My intent is:
a. On sda, copy /etc/fstab to .../fstab_sda and copy /boot/grub2/grub.cfg to .../grub_sda.cfg.
b. Exclude /etc/fstab and /boot/grub2/grub.cfg from the rsync, HOPING that the backup will therefore boot successfully from (position sdc).
c. If I want to replace the boot disk with the backup (booting the backup from position sda), I will replace .../fstab and .../grub.cfg with their ..._sda counterparts, HOPING that the backup will therefore boot successfully from (position sda).
HAS ANYONE TAKEN THIS APPROACH? DO .../fstab and .../grub.cfg ACTUALLY NEED THIS SPECIAL HANDLING? ARE THERE ANY OTHER FILES THAT NEED THIS SPECIAL HANDLING?
(3) My research SUGGESTS that (1) + (2) above are overkill, and that I should abandon the rsync_on_the_root strategy in favor of:
a. Only rsync'g /home and /etc.
b. Maintaining a list of installed packages with dnf.
c. Restoring by using Fedora 22 Live to place the (full) Fedora 22 on a new disk, manually rsync'g /home and /etc on this new disk, and then using dnf to manually re-install the packages to this new disk.
d. Periodically checking fedoraproject.org for a newer version of the Fedora 22 (workstation) Live iso.
On my system, "dnf history userinstalled" reports only 24 packages since my ...
