[PC-BSD Testing] Special FS Layout idea
yerenkow at uct.ua
Thu Jun 7 05:54:27 PDT 2012
I just found out that ZFS now supports unionfs :)
So, I want make long standing idea real - to test graceful OS patches
(which was possible for UFS, but I wanted ZFS).
I think that basically, system could have this layout:
/ (few gigs here)
/boot (few gigs here - since we could want new kernel testing)
/home (for user's data - no software here)
/usr (10-30g, basic system goes here codename USRA)
/over-usr ( it mounts --- unionfs /over-usr /usr, all PBIs and ports
and etc-configs goes here)
/var/db/pkg is symlink to /usr/var/db/pkg (will explain further)
(one extra partition, same size as /usr - codename USRB).
Testing upgrade (RFC, please feel free to comment):
1. install new kernel as kernel.new, make it nextkernel (or write it
somewhere in loader.conf as new default kernel, if possible)
2. install (ideally, simply untar or even `dd` if possible) new system
to USRB, edit fstab (change mount point for /usr from USRA to USRB), and
3. after reboot you have same all PBI-s, manually edited configs,
everything else in place, and with extra bonus new operating system (new
kernel + new base system + new installed packages)
3a. You like system - you run "make this version working", which do
(kernel -> kernel.old, kernel.new -> kernel), changes in fstab are
saved, and you need simply reboot.
3b. There's something went totally wrong (as always could be), you just
revert fstab, and simply reboot to old system.
Anyone see some caveats, or maybe some advices? :)
If not, I'll start to making test environment, will toy with upgrading 9
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