Migration planning - old system to new

Doug Hardie bc979 at lafn.org
Fri Jan 22 22:39:01 UTC 2010

On 22 January 2010, at 09:12, John wrote:

> Now that I've actually gotten the new system to boot, I need to figure
> out how I'm going to migrate everything - users, data, MySQL, NAT,
> firewall, apache, DHCP, gateway services BIND, Sendmail, etc., etc
> from
> FreeBSD 4.3-RELEASE #0: Thu Jan 22 19:44:16 CST 2004
> to
> FreeBSD 8.0-RELEASE #0: Sat Nov 21 15:48:17 UTC 2009
> Bit of a challenge, eh?
> Not only that, but I'd like to update my UID scheme from a pre-standard
> version (most of the UIDs are down in the 100s) to the new convention
> so that I'm more in-line with the rest of the world.
> My rough idea:
> 1) Create a "migrate" account in Wheel with home as /var/migrate
>   so that I can do a dump/restore on "home" without messing things
>   up
> 2) Start putting together all the pieces - trying to find update / conversion
>   scripts whenever possible.
> 3) once things get close, do the dump/retore of home, and a tar/untar
>   of /var/mail (since I'm moving it from a part of the /var filesystem
>   to a filesystem of its own - doing a dump/restore on /var is not
>   a practical migration strategy in any case)
> 4) Let people move in, try it out, see how things are
> 5) Fix everything found in #4
> 6) Try a cut-over and make sure all the network services work in the
>   middle of the night sometime, then switch back
> 7) Nuke /home and /var/mail and migrate them again to get the latest version
> 8) Do the real switch
> 9) spend a couple of weeks fixing all the things that weren't so disastrous
>   that they got picked up in #4.
> Ideas / scripts / project plans / outlines - whatever?  Maybe I should
> write a chapter for The Complete FreeBSD after surviving this...

I presume you can't bring down the old system for a few weeks to make the conversion.  Thus I would
suggest you get the new system configured the way you want without the user data and back it up so that you can restore it to that configuration easily.  Then once you have your approach established do a test conversion.  Leave the old system in production and check out the results of the conversion.  You may want to tweak your conversion approach a few times.  Then when it works fine, restore the new system and do the conversion for real.

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